home power magazine 084

Bergey1000 Watt Home Wind

Dealer Inquiries

Welcome

24 VDCBattery Charging

5-Year Warranty (Industry’s Longest) Maintenance Free Design Excellent Low Wind Performance Nearly Silent Operation Three High-Strength PowerFlex

Fiberglass Blades, SH 3045 Airfoil* Neodymium Super-Magnet Alternator AutoFurl “No Worry” Storm Protection Fail-Safe Design, No Dump Load

Required for Structural Safety PowerCenter Multi-function Controller OptiCharge Regulation for Extended

Battery Life Easy Installation with BWC Tilt-up

Towers*Patent Pending

PowerCenter Controller• 60A Wind Regulator• 30A Solar Regulator• 30A Optional Dump Load• 24 VDC DC Bus• Battery Status LEDs

1–Air is a registered trademark of Southwest Windpower, Inc. 11.2 mph (5 m/s) Average Wind Speed at Hub Height, Rayliegh Distribution.2–Whisper is a registered trademark of Southwest Windpower, Inc. Based on manufacturer’s published power curves.

The all new Bergey XL.1 is the most technicallyadvanced small wind turbine ever. It combinesexcellent low wind performance and thelegendary Bergey ruggedness, at costs wellbelow the lightweights. It comes from theworld’s leading supplier of small wind turbinesand is backed by the longest warranty in thebusiness. The XL.1 delivers on value.

Compare features, performance, price,reputation, and warranties. The new BergeyXL.1 is the clear choice for your home energysystem.

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Bergey

2001 Priestley Ave.Norman, OK 73069

T: 405–364–4212F: 405–364–2078

[email protected] SIMPLICITY•RELIABILITY•PERFORMANCE

© 1999 Bergey Windpower

Astropower

four color on negatives

full page

“independent ad” from HP80 page 21

this is page 5

HOME POWERTHE HANDS-ON JOURNAL OF HOME-MADE POWER

10 Solar Earthship

Jeffrey Evans installed therenewable energy system inhis earthship six years ago.In that time, he has learneda lot about load manage-ment, efficiency, and exactlywhat can be expected fromRE. His commitment torenewables has paid off withcomfortable independence.

22 Bigger and Better

America’s preoccupationwith more is not often agood thing. But when itcomes to solar energy, wehave no complaints. Steveand Debra Davidsoninstalled almost 20 KW ofphotovoltaics to power theirGeorgia plantation home.

34 What Blackout?

Joe Schwartz and RichardPerez design a battery andinverter backup powersystem for carrying youthrough pesky periods ofutility ineptitude. The perfectbeginnings of a renewableenergy system.

44 Solar Hot Water Basics

Ken Olson kicks off a newfocus in Home Power byintroducing the basics ofsolar hot water systems, theequipment, and pros andcons for various climates.

Features

Issue #84 August / September 2001

More Features

56 African Solar Solution

Grace Birnie’s job in Benin,West Africa took her to asmall village. A simplephotovoltaic system powersa computer for work, and herhome appliances too.

64 Solar Logging...Really

Rico and Mary Meleski usesolar electricity to help themclear trees, and mill thelumber without the use ofgasoline.

88 Propane GeneratorConversion

Herb Levitin installs apropane conversion kit on a5 KW Generac generator.

Homebrew

74 LED Flashlight Conversion

Peter Jones converts a threeC-cell Mag-Lite to LEDs.

GoPower

98 Debunking the Myths

There are a lot ofmisconceptions—bothpositive and negative—about electric vehicles. ShariPrange aims for the truth.

104 Why Convert?

What are the environmentaland economic benefits ofturning a dying gas car intoan EV? Mike Brown knows.

116 Power Politics

PG&E goes bankrupt, righton schedule.

120 Independent PowerProviders

Fuel cell misrepresentation;California and RE rulings;grid-tie inverters; more.

124 Code Corner

Kinds and uses ofovercurrent devices.

128 Home & Heart

Mice ain’t nice!

136 The Wizard

Basic principals of Wizardry.

150 Ozonal Notes

Richard Perez hasflashbacks. Also, Jason seesthe light.

Access DataHome Power

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Editorial:Phone: 530-475-3179Fax: 530-475-0836

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Email: [email protected]: www.homepower.comPaper and Ink Data

Cover paper is 50% recycled (10% postconsumer / 40% preconsumer)Recovery Gloss from S.D. Warren PaperCompany.

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Home Power (ISSN 1050-2416) ispublished bi-monthly for $22.50 per yearat PO Box 520, Ashland, OR 97520.International surface subscription forUS$30. Periodicals postage paid atAshland, OR, and at additional mailingoffices. POSTMASTER send addresscorrections to Home Power, PO Box 520,Ashland, OR 97520.

Copyright ©2001 Home Power, Inc.

All rights reserved. Contents may not bereprinted or otherwise reproduced withoutwritten permission.

While Home Power magazine strives forclarity and accuracy, we assume noresponsibility or liability for the use of thisinformation.

Regulars

Access and Info

This paper is recycled and recycleable.

8 From Us to You

80 HP’s Subscription Form

81 Home Power’s Biz Page

132 Happenings—RE Events

138 Letters to Home Power

153 Q&A

156 Writing for Home Power

157 MicroAds

160 Index to Advertisers

Cover: Blackouts affect thousands, everywhere and every year—how will your house look during the next one?

More Columns

Columns

114 Word Power

Parallel circuits defined.

Things that Work!

84 A Big Brand Refrigerator

Finally the big timers arelearning. This 18.5 cubicfoot Maytag refrigerator isefficient enough for use in asolar-powered home!

Guerrilla Solar

82 Guerrilla 0015

Somewhere in an unnamedCanadian city, PVs hangunobtrusively from anapartment building balcony.

Wrench Realities

92 Welding Cable Viability

The truth about UL listingand using welding cables forbatteries.

They Do It on RE!96 Amazing Uses of RE

A solar-powered glassarmonica!

Comm Power

108 Remote Internet at Last!

Welcome to StarBand, thesolution for off-grid access.

Home Power #84 • August / September 20018

Mike Brown

Drake Chamberlin

Sam Coleman

Windy Dankoff

Jeffrey Evans

Liz Gillette-Ford

Eric Grisen

Kathleen Jarschke-Schultze

Peter Jones

Todd King

Stan Krute

Don Kulha

Tom Lane

Herb Levitin

Don Loweburg

Ken Olson

Karen Perez

Richard Perez

Jason Powell

Shari Prange

Benjamin Root

Connie Said

Joe Schwartz

Linda Tozer

Wightman Weese

Michael Welch

John Wiles

Dave Wilmeth

Ian Woofenden

Rue Wright

William Zeitler

Solar Guerrilla 0015

People

“Think about it…”

Desert and tundra areecosystems, but without PV,your rooftop is a wasteland.

–Eric Grisen

Star PowerAt the Arcata Renewable Energy FairThe tenth annual Arcata (California) Renewable Energy Fair was held inlate April. For the past ten years, we have tried without success to getcelebrities to come to the fair, knowing what star power can do to boostinterest and attendance.

This year we found out that Woody Harrelson, well-known actor andactivist, would be coming through town during the weekend of the fair, andhe agreed to speak. Harrelson was on a “Simple Organic Living” (SOL)bike/bus tour that started in Seattle, Washington and ended in SantaBarbara, California. His tour was intended to demonstrate that the planetwill not survive unless we all choose to live lightly on the earth. Harrelsonwalks his talk (or rather rides his talk). He bicycled the entire tour route,and he runs his support bus, called “Mothership,” on hemp oil andvegetable oil (biodiesel).

Harrelson buys organically grown hemp clothing, runs all the Mothershipappliances on solar electricity, and eats only organically grown foods. Hewas very pleased with his visit to Arcata, especially when he found out thatCCAT would donate 250 gallons of their biodiesel (see HP82, page 58) toreplenish his fuel supply.

In all the years of the Arcata Renewable Energy Fair, we have never had alarger crowd than the 2,500 who arrived to hear Harrelson’s importantmessage. Harrelson fired up the crowd, big time. By the time Woody wasdone, it felt like many in the audience were ready to change their ways.

You and I can make a difference, but celebrities like Harrelson can have abroad ripple effect. The bottom line? If you run an RE fair, it really helps todo whatever it takes to bring in the extra attendance—including attracting abig name to the event.

–Michael Welch

A Division of ARISE Technologies Corporation

!"#$%& %%&

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The newly discovered “energy crisis”masks the real crisis that motivatedus to live on solar and wind in thefirst place—pollution. Moving offcoal-fired, nuclear, and centralizedhydro power is about endingmassive contamination of our air,water, and soils. Conservation iseasy once you understand the realissue. As legendary British bluesmanJohn Mayall says, “Nature’sdisappearing. It’s goin’ down—doyou care?”

The EarthshipAn earthship is an independenthome built on principles of

10 Home Power #84 • August / September 2001

iving with renewable energy puts a smile on my face every time I thinkabout it—even more today than it did in 1995 when we first built the

PV system for our earthship (see HP59, page 6). We’ve gone throughsome adjustments in six years of living off-grid, and we are now sailingcomfortably on the high solar desert of the Colorado Plateau.

Jeffrey Evans©2001 Jeffrey Evans

The Evans earthship in Colorado is powered by renewable energy and built with recycled and earth-friendly materials.

South-facing windows facilitate passive solar heating.

sustainability. It is made of materials readily availableanywhere in the world. It functions as a passive solarhouse, with sunlight heating thermal mass walls madeof rammed earth, tires, and adobe. It supplies its ownpower from the sun and wind, and collects its ownwater from the sky with a rooftop rainwater collectionsystem. The design represents an effort to change ourmethods of l iving, our ways ofthinking, and our understanding ofthe environment.

While enthusiasm is crit ical,practical knowledge of how todesign and build a home and anenergy system to meet your specificneeds is not so common. We have,through a combination of diligence,necessity, and trial and error, finallyreached solid ground with ourrenewable energy (RE) system.

We started out with a 1,500 squarefoot (140 m2) structure and a verymodest power system. Over theyears we increased the size of thehouse to 3,000 square feet (280m2), and gradually rebuilt and

11Home Power #84 • August / September 2001

upgraded many of our solar-electric systemcomponents. Expanding the size of the earthship was inthe original plan. The additional size really didn’t impactour solar needs, because we continued to follow a“lights on in the space you’re in” conservation policy.We have more lights and outlets, but our consumptionhasn’t changed much.

It is a beautiful, comfortable, energy efficient, and low impact home.

Water is collected from the Colorado sky by roof catchment.


Solar & Wind

How We StartedOur original system was of modest proportions: eightKyocera 51 watt panels, an Air 303 wind genny, and aTrace 2,500 watt modified square-wave U-seriesinverter in a 12 volt nominal system.

The first big problem from our original installation camewith the batteries. The first set, ten T-105s, were usednot only in the construction phase to run tools, butduring our learning phase, when we made most of ourmistakes. I didn’t know what “equalization” meant untilseveral years of system use had passed, and we didn’thave an engine-generator.

Equalization is a periodic, controlled overcharge tobring all the battery cells to the same level of charge orvoltage. This reduces sulfation, mixes the electrolyte,and extends battery life. Equalization of flooded lead-acid batteries requires overcharging the battery until theindividual cells reach 2.6 volts per cell. That means 15.6volts for a 12 VDC nominal system.

Check with the manufacturer for equalizing specifics foryour particular batteries. And never attempt to equalize

sealed batteries. Overcharging sealed batteries willseriously damage them! In our system, when thebatteries began to perform poorly, we added a Generac4000 engine-generator to the system, and started tomaintain the batteries properly.

A Closer LookThe next concern, which then became my primarytarget, was the charging system itself. The originalsystem was built with an on/off switching device thatbroke the panel charge off at about 14.2 volts. Thismeant that we could never equalize with the panelsalone, no matter how much sunlight was available.

After numerous discussions with installers, dealers, andvarious experts in the field, I found an installer (LeifJewel of Ridgway, Colorado really knows his stuff) whocould remove the switch system and replace it with aTrace C40 charge controller. This little wonder broughtmy PV system back to life. One fully automated, solid-state, pulse-width modulated charge controller allowedme, for the first time, to manage my system with thesun. And my batteries were so happy.

Recycled tires with rammed earth fill make cheap and energy efficient walls.

Earthen stucco creates energy-storing thermal mass.

Every room receives solar gain.

A solar hallway along the south wall connects all rooms.


Solar & Wind

Earthship Loads

Load Total Hours Watt-hours Days Watt-hours Avg. WH PercentWatts per Day per Day per Week per Week per Day of Total

Sun Frost RF-12 60 7.00 420 7 2,940 420 35.0%3 CF lights 39 3.00 117 7 819 117 10.0%2 Surge protectors 25 4.00 100 7 700 100 8.5%Gas oven 600 0.25 150 4 600 86 7.0%Electric piano 90 1.00 90 5 450 64 5.5%Washing machine 110 1.00 110 4 440 63 5.0%TV 60 1.00 60 7 420 60 5.0%Computer CPU 55 1.00 55 7 385 55 4.5%Water pump 108 0.50 54 7 378 54 4.5%Iron 1,500 0.25 375 1 375 54 4.5%Toaster 900 0.25 225 1 225 32 2.5%Hair curler 750 0.25 188 1 188 27 2.0%Monitor 14 1.00 14 7 98 14 1.0%Printer 12 1.00 12 7 84 12 1.0%Battery charger 8 10.00 80 1 80 11 1.0%Stereo 30 0.50 15 4 60 9 1.0%VCR 19 0.50 10 4 38 5 0.5%CD 10 0.50 5 4 20 3 0.5%Radio 10 0.50 5 4 20 3 0.5%Vacuum cleaner 78 0.10 8 2 16 2 0.5%

Totals 2,093 8,336 1,191 100.0%

More ProblemsWhile the system was given new lifeafter this, our loads continued tomake their demands, and take theirtoll on our batteries. One of theculprits an RE system will encounteris the conventional 1/2 HP ACpressurizing water pump. Thisenergy bandit has a significant motorsurge.

I literally ran to the voltage meterevery time this monster kicked on,like a frightened deer bolting fromoncoming headlights. The voltagewould get as low as 11.5 V, andunder load in the best of times wouldbe 12.2 V. With each passing month,the meter would dip farther into thewhite zone as the pump began itssluggish mantra.

I was desperate for an alternative. One day I discoveredBackwoods Solar. The good folks there told me that thiswas not such a difficult problem to solve after all. Withgreat trepidation and after intense discussions, I

ordered a Shurflo AC pressurizing pump (model #2088-594-154, 115 VAC; 0.94 amps maximum. Actualrunning amps will depend on gpm flow rate). I was sofreaked out that I bought two. (One is still in the box.)

Natural building materials lend themselves to artistic creativity.

per load depending on the waterlevel setting.

As for drying, it’s all solar now. Theold gas dryer went bye-bye with thewasher. So I no longer clamberdesperately over everything in mypath to get to the voltage meter.When I do, I find that the meterbarely moves when the washer runs.In combination with the low energywater pump, I can take care oflaundry needs just about anytime Iwish.

Early in the game, we had replacedour 1950s Servel propanerefrigerator with a Sun Frost AC RF-

12. At 70°F (21°C), this refrigerator/freezer consumesabout 350 watt-hours per day. This is a premieremachine as well, familiar to most RE users. So as wemade these upgrades, I was very satisfied with myself.After all, the problems were being eliminated one byone.

Still, there was the storage problem. Even with all thechanges, the batteries were losing ground with everypassing day. After several years of heavy duty use andabuse, we were seriously short on energy during thewinter months, November to March. It was time toreplace the batteries, even though there was still somelife in the six-year-old T-105s.

New BatteriesWhich way to go—another set of T-105s, or move up tothe L-16 level? I began yet another furious session of


This little baby has a very small surge—just enough totake my inverter out of sleep mode. And it uses a smallamount of energy. I installed it in-line, bypassing the 1/2hp AC pump with a valve, and leaving the old pumpinstalled in case I ever have to use it again.

Is It Over Yet?That problem solved, things began to look up. No moregiant surges and depleting energy moments. Or so Ithought. But the batteries continued to decline, chargingquickly, but losing strength quickly after sundown. Icontinued to be on the lookout for low voltage, worryingabout use with every flick of the switch. I realized that Ihad to take a closer look at consumption.

I discovered that my washing machine was nearly asbad as my water pump when it came to energyconsumption (and it didn’t clean worth a darn either).With a rated draw of about 600 wattsand a significant surge (enough toshut down my inverter whencombined with the old water pump),this modern beast could only be runon the sunniest days anyway. Icouldn’t have been happier to see itin the back of a pickup heading forthe Salvation Army store. I didn’teven wave.

SolutionsIf anything could surpass thatmoment of joy, it would have to bethe day I picked up our freshlyshipped Staber System 2000 heavyduty washing machine. Its runningpower draw is under 200 watts, andit consumes about 1/2 the water of aconventional machine. Water usagevaries from 16 to 22 gallons (60–80 l)

The power panel includes a modified sine-wave inverter and 60 amp controller.

888 watts of PV, and a small wind generator cover the electrical loads.

MODEL U2512

Batteries: Eight Trojan L16Hlead-acid batteries, 395 AH each

for 1,580 AH at 12 VDC

Inverter: Trace U2512 modified sine-wave,2,500 watts continuous at 120 VAC

Shunt

Ammeter:System amps

Volt Meter

AC Distribution Panel:15 amp breakers,to 120 VAC loads

DC Distribution Panel:15 amp breakers,to 12 VDC loads

Charge Controller:Trace C60, 60 amp

Shunt

Ammeter:Wind amps

AC Charger:Diehard,60 amp

Internal Combustion Generator:Generac 4000, 4,000 watts

continuous at 120 VAC

Breaker:60 amps

Wind Generator:Southwest Windpower

Air 303

Photovoltaic Array: Eight Kyocera LA361G51S PV modules,51 watts each for 408 watts at 12 VDC

Photovoltaic Array: Six Solarex VLX80PV modules, 80 watts each for 480 watts at 12 VDC

Ground

DC Disconnects:Inverter, 250 amp

DC Loads, 100 ampPV arrays, 60 amp

Fuse:0.5 A

To Batteries:Manual

connectionwhen needed


Solar & Wind


Solar & Wind

research, looking at all the alternatives in the batteryworld. I assessed cost, weight, availability, and chargingfactors before buying eight 395 AH high-capacity TrojanL-16s from a local supplier.

These batteries weigh 120 pounds (54 kg) each, whichis about what I weigh. Needless to say, it was avertebral nightmare to get them into the newlyexpanded battery box. In fact, I had to put the batteriesonto the box base, and then build the rest of the boxaround them.

The actual output of my PV array was around 350watts, with periodic production from the Air 303. I settledfor eight batteries when I really wanted ten. Still, thenew pack of eight high-capacity L-16s increased mystorage capacity from about 1,100 amp-hours to 1,580amp-hours.

I figured that with my newly sized loads, I could operatethe eight batteries at around 20 percent depth ofdischarge, where I had been closer to 50 percentbefore. (Thanks to Kerry Kalarney of Sundance Solar inMontrose, Colorado for advice on battery installation.)We installed the batteries and did some initialequalization charges from the generator. Just before the onset of winter, I began to enjoy my new-foundpower.

Until winter actually arrived, that is... Much to mypersonal aggravation, there was less sun than usual,and production was dismally low—not enough to bringthe batteries up to full charge levels. The following fewmonths saw generator charges every three or fourdays, or so it seemed. Back to the frightened deer look,with long, ritual staring at the meters.

After repeating this experience on a regular basis, Ibegan to see the light. I needed more PV modules!

Great sun gods, another project in my long trek towardthe unattained vision of energy self sufficiency!

New PVsSo, as soon as the clouds cleared and the groundthawed, I began the installation of six Solarex VLX80modules. These PVs are rated at 80 watts at 20°C(68°F). To reflect real world PV operating temperatures,the rated output on all modules needs to be derated byabout 20 percent.

I planned to put them on a new pole, set in the bermbehind the new addition to the earthship. This proved tobe the moment of truth. Could I, a classic novice,overcome the massive levels of fright I experienced atthe mere thought of doing this myself, and install myown modules?

With a little help from my friends (Glen Harcourt of SolarWorks in Placerville, Colorado, I am forever indebted toyou), I decided to go forward. Extensive researchfollowed.

Aside from wire runs and laying conduit, the primaryproblem was how to get power from two arrays into mysystem without blowing everything to smithereens. Theanswer? A Trace C60 charge controller. The new arraygenerates 80 watts per panel, rated at 17 volts and 4.71amps times six panels. That is 480 watts of production,in addition to my original array’s rated output of 408

Evans System CostsOriginal Installation

Item Cost (US$)8 Kyocera 51 watt PVs with rack $3,000Trace U2512 inverter 2,500Generac 4000 generator 1,250Control box, poles, gauges, etc. 1,200Air 303 wind generator with tower 1,00010 Trojan T-105 batteries, 6 volt 800Diehard 60 amp charger 250Trace C40 charge controller 200

Original Installation Total $10,200

Upgrades

Item Cost (US$)6 Solarex VLX80 panels $2,3008 Trojan L16H batteries, 6 volt 1,500Miscellaneous 500Top-of-pole mount rack 300Trace C-60 charge controller 200

Upgrades Total $4,800

Grand Total $15,000

Eight Trojan L16Hs store 1,580 amp-hours at 12 volts.


Solar & Wind

watts. This gives a total of some 888 rated watts.Derating this number by 20 percent to reflect PV outputat real world operating temperatures, I came up withabout 710 watts of actual PV production in full sun.

Maximum charging during full sun is about 50 amps.This is confirmed by the actual reading on the meters atthe power center. But the joy, the sheer joy, of seeingproduction on this little home system run up to 40 and50 amps as soon as the sun lights up is indescribable.

My battery maintenance routine has become addingdistilled water to my batteries on a monthly basis andmonitoring to make sure that I am getting regularequalization periods. I have not used my generator allwinter. Equalization is available regularly from thepanels alone.

Time to EnjoyWith the arrival of the new battery pack, I have 1,580amp-hours to work with (395 AH x 4 = 1,580 AH). At 20percent depth of discharge, that gives me 316 amp-hours to use (1,580 AH x 20% DOD = 316 AH), or 3,792watt-hours (316 amp-hours x 12 volts = 3,792).

As the load chart shows, we consume, on average,1,191 watt-hours of energy per day. At full charge, thatleaves us with about three days of stored energy toburn. Of course, at 20 percent DOD, I have a lot ofenergy to play with if I need to use more.

In addition, with my new PV array, I can produce some3,550 watt-hours on a sunny winter day (710 watts x 5hours = 3,550 watt-hours). I am producing nearly threetimes what I might normally use (1,191 watt-hours x 3 =3,573 watt-hours, compared to 3,550 watt-hours ofproduction).

My adjustments on the load side over the last four yearsinclude removing two energy hogs (washing machineand water pump), and replacing them with energyefficient units. In all this, I increased the number ofappliances available, building more capability andversatility into my home use. I also eliminated allserious surges, while at the same time decreasing theoverall energy load.

We have invested $15,000 in this system and haveused it for six years. At an average cost of $150 permonth for utility-powered homes, in another 28 monthsour system will have paid for itself.

My one remaining fear has yet to be addressed—inverter failure. Somewhere out there, there’s a sine-wave inverter waiting for installation in our earthship.But it is an expense that I hope to delay for some yearsto come. The modified square-wave inverter has itsdrawbacks, such as noticeable buzzing in my electric

piano, but to tell the truth, we don’t notice it that muchthese days.

Sustainable Living, Sustainable EnergyThe earthship experience, which has led me into theworld of solar energy, continues to be an enlighteningencounter. My life, and the life of my family, has beenchanged forever. I have learned much about the naturalworld, as well as about our comprehensive disregard asa society and culture for nature itself.

This trek into a new life has taken me into what israpidly becoming the dominant issue of the twenty-firstcentury—recognizing the massive levels of degradationof our air, water, and soil. I add my voice to the growingchorus of humanity in their call for sustainable livingpractices, including how we build and where we get ourenergy.

AccessJeff Evans, PO Box 2827, Grand Junction, CO 81502970-256-1376 • Fax: 970-256-1373 • [email protected]

Solar Works of Sawpit, Glen Harcourt, PO Box 306,Placerville, CO 81430 • Phone/Fax: [email protected] • Expert PV education, supply, waterfiltration

Solar Survival Architecture/Earthship Biotecture,Michael Reynolds, PO Box 1041, Taos, NM 87571505-751-0462 • Fax: [email protected] • www.earthship.orgEarthship resources, PV equipment

Sundance Solar Designs, Kerry Kalarney, 68238 EMiami Rd., Montrose, CO 81401 • 888-786-3374Phone/Fax: 970-252-1978 • [email protected] • Expert information, batteries, PV

Backwoods Solar Electric Systems, 1395 RollingThunder Ridge, Sandpoint, ID 83864 • 208-263-4290Fax: 208-265-4788 • [email protected] • Expert information, waterpumps

Alternative Power Enterprises, Leif Juell, PO Box 351,Ridgway, CO 81432 • 800-590-5830 or 970-626-9842Fax: 970-626-9826 • [email protected] • Expert consultation,charge controller, power center

18Home Power #77 • June / July 2000

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carlett O’Hara’s precious Tarain Gone with the Wind was amythical plantation in Georgia that

depicted a world-famous image of thesouthern plantation lifestyle. Steveand Debra Davison’s solar-electricplantation in central Georgia—I call itthe “New Tara”—has become alegend in the south. And it’s only inthe beginning stages.In the spring of 1999, Steve Davison contacted RogerLocke of Hutton Communications in Atlanta, Georgiaabout his boyhood dream of using solar energy.Because Hutton is the Siemens solar-electric distributorfor the southeastern United States, Steve asked Rogerto design an initial system for the New Tara.

Our experience with a similar job in Florida (HP70, page15) and with systems around the world since 1977prompted Roger to include Energy ConservationServices (ECS) in the design team meetings. Within acouple of weeks of the initial contact, Steve, Roger, andI met on a Georgia hillside, setting Steve’s solar dreaminto action.

An avid Home Power reader, Steve Davison wanted touse solar energy to power his future home. But he alsowanted to build a plantation field of solar modules tofeed green power back into the grid and make itavailable to his neighbors. Before the Davisons builttheir hillside home, Steve wanted to install a solar-electric system for their temporary home on theproperty, and for electricity for building their permanenthome.

His goal, even in the beginning stages, was to install asolar-electric system that would produce excess powerfor sale to the rural electric grid. The long-range planwas to make New Tara a showcase of the latest solarand energy efficient technologies, with a goal ofencouraging other southerners to “give their sun a job.”

All About the SystemNew Tara’s system started with 192 Siemens 100 wattsolar-electric modules and eight Trace SW5548inverters. The storage battery bank contained 36 Deka1,247 amp-hour 12 volt batteries wired for 11,223 amp-hours at 48 volts. Utility power and a 100 KW OnanCummins diesel generator were installed for backupshould the solar-electric system malfunction, or if theneed for backup power arose during inclement weather.

The job started in June of 1999, using a pole-mountedarray system with 24 Direct Power and Water (DP&W)racks in three north/south rows. Eight racks were

192 Siemens SR-100 photovoltaic modules provide the power for the building and future operation of New Tara.

Tom Lane, with Linda Tozer©2001 Tom Lane


Photovoltaics

aligned in each row. Each rack holds eight SiemensSR100 modules for an initial array of 192 solar-electricmodules. The south-facing hillside pasture providedenough room for the present system and allowed forfuture expansion.

Sets of three racks, one from each of the rows, werecombined at the rack in the middle row with eightcustom-made combiner boxes. Each of these customboxes feeds a Trace C40 controller with a digital voltagemeter (DVM) in the power conditioning and distributionbuilding.

We needed 84 linear feet (26 m) of space on theDavisons’ property to install these eight DP&W racks.Each rack was installed 12 feet (3.6 m) from the nextone, atop six inch (15 cm) schedule 40 steel poles.Poles were painted with Rust Destroyer rust convertingprimer, and then painted with an ICC ceramic coating.

The pole racks made for easy east/west alignment onthe rolling hillside. Installed this way, the arrays are infull sunlight year-round from 8 AM to 5 PM. Using trackracks would have required almost 300 linear feet (91 m)of spacing, instead of the 84 feet (26 m) required withthe pole racks, to prevent east/west shading fromadjacent racks. Once the poles had been set inconcrete, all 24 racks in the array were assembled.Then the 192 modules were attached and wiredtogether in 48 volt subarrays of eight modules each.

Five ECS wrenches took just one day to install the 192modules on the 24 racks. The DP&W racks have sixnorth/south adjustable positions. Using the solar panel

angle guide in HP36 (page 14) allowed eightnorth/south adjustments a year. All 24 tilt angleadjustments can be made in less than thirty minutes byone farm hand! Thank you Jeff Randall of Direct Powerand Water for this rack design!

The power room includes eight Trace SW5548 inverters capable of 22 KW at 220 VAC.

Steve and Debra Davison are psyched to set an exampleby spinning their meter backwards.


Photovoltaics

Rack ConfigurationAll eight Siemens SR100 modules on each rack wereconfigured individually as 6 volt modules at 12 ampseach. These eight 100 watt modules were wired inseries to create a 48 volt subarray at 12 amps. Thissimple wiring technique only requires one #8 (8 mm2)wire in series between each module. Two #8 wires wereused for the run from each rack to the combiner box,where three racks were combined and grounded.

The positive leg from each rack was wired to a 20 ampRK5 time-delay fuse in a box on the pole. Then it wasfed to a combiner box located next to each middle rackrow. Eight Trace C40 controllers with DVMs were wiredto 60 amp circuit breakers on two of the four TraceDC250 disconnects used with each pair of series-stacked SW5548 inverters. Each Trace C40 was fedfrom a combiner box by a separate wiring run of #2 (33mm2) wire.

Fast-acting polyphaser lightning protection with 50 ampresets for both the positive and negative legs in parallelwere used in every box. The original IS-48VDC-30Apolyphaser lightning protectors in the combiner box all

had to be replaced. They were tripping the positive andnegative polyphaser disconnects on hot summer dayswhen the controllers were at open circuit voltage with afull battery bank. IS-60VDC-30A polyphasers were therequired upgrade.

In addition to grounding each combiner box, a dripirrigation system was installed for the entire array toproduce better grounding during extended hot dryweather and for additional lightning protection. Underfull sun, each three-rack subarray produces 36 to 38amps at 48 to 56 volts from each of the eight combinerboxes. The system delivers a total of 13,824 watts (288amps at 48 volts) to the battery bank.

Battery BankThe battery bank, weighing 36,000 pounds (16,330 kg),consists of thirty-six 12 volt, 1,247 amp-hour Dekabatteries wired as one large 48 volt battery bank. Theeight Trace SW5548 inverters were wired in four groupsof two inverters. The Deka batteries had two positiveand two negative connectors on each battery terminal.Deka supplied heavy gauge #4/0 (107 mm2) cable toconnect each group of four 12 volt batteries in series at48 volts.

All parallel connections in the huge battery bank werewired with two positive runs and two negative runs of#4/0 cable. Great effort was made to create equaldistance wire runs from each of the eight TraceSW5548 inverters to the battery bank. However, havingthe extra #4/0 cable on all parallel battery connectionshelped create an even draw from the eight positive andeight negative inverter cable connections on the batterybank’s terminals.

Four Trace TM500 battery monitors with 48 VDC pre-scalers were used with each pair of series-stackedSW5548 inverters. This provides a second digital meterreading confirmation on the inverters and the C40DVMs. They were all wired to separate shunts to giveindependent information on battery bank voltage.

The output from three pairs of inverters goes to an autotransfer switch. The fourth pair's output goes to amanual transfer switch. From there, it is sent to its ownAC subpanel. One pair of inverters powers the mainhouse. The second pair powers the pool house. Thethird and fourth pairs are split up to power the airconditioning units and pool pumps. The inverters arenow in LBX (Low Battery Transfer) mode, whichtransfers loads to the grid when battery voltage reachesa low set point. We will be using "sell" mode in thefuture

Recycled rubber pool mats were placed under thebattery bank to separate the steel cases from the

The twenty-four Direct Power and Water PV racks can beadjusted for seasonal angle in less than one minute each.


Photovoltaics

PV Subarray: Eight (one shown) 2,400 watt sub arraysof twenty-four Siemens SR-100, 100 watt PV modules.

Modules internally wired for 6 VDC, witheight modules per pole mount wired in series for 48 VDC

Total Photovoltaics: 192 PVmodules on 24 Direct Power and

Water pole mount racks,for 19.2 rated kilowatts at 48 VDC

Fuse: 20 amp RK5time delay

PV Combiner Box:Eight (one shown) combiner boxes

with IS-60VDC-30A Polyphaserlightning arrestors

PV Disconnect:Four 60 amp

breakers

To subarray 4 To subarray 3

Tosubarray 2

54.5 54.5 54.5 54.5Trace 4.0 Kilowatt

Trace 4.0 Kilowatt

54.4

DC Disconnect: Four (one shown) Trace DC250s, (two units also contain PV array disconnects, shown)

Charge Controllers: Eight (four shown)Trace DVM/C40, 40 amp charge

controllers, one for each sub-array

Meters: Four (one shown)Trace TM500 amp-hour meters,

one for each stacked pair of inverters(meter wiring and shunt not shown)

Inverters: Eight (two shown) Trace SW5548 sine-waveinverters, stacked in pairs for 220 VAC,

(six units are grid-tied, two are stand-alone)

Batteries:Thirty-six Deka 12 volt lead-acid batteries,

1,247 amp-hours each,wired for 11,223 amp-hours at 48 VDC

Negative busomitted for clarity

BatteryDisconnect:Two 250 amp

breakers


Photovoltaics

concrete. Water Miser vent caps replaced all of the 108original battery caps. These flip-top caps make thebimonthly inspection and watering of the batterieseasier, help reduce hydrogen fumes, extend wateringintervals, and prevent an externally created spark fromcausing an internal battery cell explosion.

All battery terminals were lightly covered with petroleumjelly before wiring, and with lithium automotive greaseafter wiring to prevent corrosion. Sixteen batterytemperature sensors were also used—one for eachcontroller and one for each inverter. These adjust thecharge setpoints for different battery temperatures, andinsure full charge in all temperature conditions.

Power RoomIn this installation, the battery room was separated fromthe power conditioning room by an insulated wall. Theceiling, walls, and both of the vented roll-up garagedoors were coated with LO/MIT-1 radiant barrieraluminum and fire retardant coating. This reduces heatgain inside the building and provides a shield againstoutside electromagnetic pulses or interference.Because of its spectral reflectivity (95%), the radiantbarrier also helps illuminate the room.

The outside walls were insulated, and a continuousridge vent was installed in the roof to vent the batteryroom and to keep the room as cool as possible duringextremely hot weather. During the day, a solar-poweredroof-mounted fan with its own PV module is used toexhaust heat and fumes from the battery room.

A second solar-powered rooftop fan exhausts theintense daytime heat from the eight Trace C40s and theeight inverters in the power conditioning room. Thesummer temperatures of central Georgia days added agreat deal of heat to the power conditioning room, inspite of our best efforts to minimize temperatures.

Magic MaterialsIt’s always been amazing to me thatwe capture light from a star withsilicon crystals made from sand, oneof the most common materials onthe planet. Then we store the powerin lead. These common materialscreate the magic for carbon-base lifeforms.

I normally try to size 0.85 to 1 watt ofrated PV capacity per pound ofstorage lead for large arrays (forremote homes with largegenerators). I invented this formulamyself as a relationship of lead tosunlight—it’s swamp hillbilly PVsystem sizing. The Davison system,

before expansion, was just over 0.5 watts per pound oflead. We are now adding 120 more SR100 modules to15 more DP&W racks. This will bring the PV to leadratio to 0.86 watts per pound of lead.

New Tara Load ConsiderationsSteve Davison’s ultimate goal is to sell power to thelocal utility. During hot summer days, the temporaryhome site uses all the power the array creates in a day.For Steve to achieve future goals in his new home (tobe finished in 2001), he needed to employ a systemsapproach for selecting materials and systems. Tofacilitate this, I introduced Ken Fonorow to the project.Ken is president of Florida Home Energy andResources Organization (Florida HERO), and anationally recognized building science specialist andEnergy Star expert.

After reviewing the new house plans and completing astructural heat gain and loss analysis, Ken

Eighteen tons of Deka lead-acid batteries provide 11,223 amp-hours of storage.

108 Water Miser cell caps recombine gases createdduring charging, minimizing the need for watering.


Photovoltaics

recommended a range of measures to make the newhome more energy efficient. Clearly, there is arelationship between the efficiency of a home and itsenergy requirements. Among the recommended energyefficiency measures were:

• An unvented crawlspace with a vapor barrier installedon the ground and air-sealed to the stem walls.

• Wall-sprayed R-20 cellulose insulation installed in 2by 6 inch wall stud cavities.

• Double-pane, spectrally selective wood-framewindows with a solar heat gain coefficient (SHGC) of0.4 or less.

• An unvented cathedral attic with R-36 Icyneneinsulation installed directly to the underside of theradiant barrier metal roof (to insure that the heatingand cooling equipment and distribution ductworkwould be within the thermal envelope of the home).

• An open loop geothermal or ground-coupled heatpump system, zoned to minimize the startup draw.

• An advanced load control system, to ensure thatmultiple systems don’t start up at the same time andthat they are rotated operationally.

• An LP gas clothes dryer, stove, oven, and acombination of LP gas and solar thermal pre-heaterfor domestic hot water.

• Compact fluorescent bulbs and other low wattagelighting systems.

Besides building his new home and creating a powersource to feed back to the local utility, Steve Davisonhad another important goal for developing New Tara.He wanted to prove to his friends and Atlanta businessand social colleagues that it waspossible to power any appliance in aconventional southern home withsolar electricity.

I was quite stunned to realize whatthe loads will include in a typicalsouthern summer day. During theafternoon, operating this southernhome meant operating two airconditioning systems, a dishwasher,clothes washer, clothes dryer,electric range, and oven. Since hotwater was used for laundry, thismeant that a 4,500 watt electricelement in the water heater could beoperating at the same time as allfour electric burners on the stoveand the oven—approximately10,000 watts!

The Davisons’ future home would have a solar hotwater system as backup to an LP gas water heater. LPgas for the dryer or for cooking was not feasible in thepresent home. Intermittent water use also meant that a1-1/2 HP well pump repeatedly started and stopped.The heat from midday cooking and cleaning also addedto the household’s tremendous radiant heat gain. Withroutine outside humidity over 80 percent andtemperatures in the upper 90s, both air conditioningsystems ran at full speed, exploding the home loadrequirements.

ECS’s project supervisor James Dempsey, electricalwizard John Ault, and I had to face a rapid loadmanagement learning curve. Managing this inordinatelylarge load was further complicated by the addition ofthree 1 to 1-1/2 HP pool and spa pumps that operated24 hours a day. Because the recently built pool andcabana house would one day also be part of New Tara,we added sixteen 4 by 12 foot (1.2 by 3.6 m)Aquatherm Industries solar collectors to provide enoughheat to allow the pool to be used most of the year.

Original New Tara design specifications called for sixTrace SW5548 inverters. With the additional householdload parameters, eight actually were required. JamesDempsey worked on all the household loads with localelectrician, Joe Rainey. Joe put in automated transferswitches for all eight dual inverter groups, and an 80amp AC circuit for each inverter’s battery charger.

We balanced all transfer switch loads to the home foreach dual inverter group. We also automated backuppower for battery charging with both the 100 KW Onandiesel generator and the local rural utility grid. This wasin case the solar-electric system malfunctioned, or if itneeded backup power for battery charging.

A huge 100 kilowatt Onan Cummins diesel generator provides backup.


Photovoltaics

Solving ProblemsSpecial credit goes to Jim Jackson of On-Site Power.The local rural utility was notorious for having short-term blackouts that resulted in the 100 KW generatorstarting unnecessarily. Jim designed a relay packagethat prevented the generator from starting in the eventthat grid power from the utility was not available, aslong as the Trace inverters were operating correctly.

Two SW5548 inverters that are dedicated to the airconditioning and heating system kept tripping theirinternal breakers when the main air conditioner turnedon during the hot summer days. The tripping continuedeven with no other load and an added start capacitorrelay. The air conditioning distributor, technicalliterature, and factory engineers reiterated that themaximum AC starting surge at locked rotor amps was65 amps at 240 volts.

Trace specifications indicated that the dual SW5548scould handle that load. We found that it often could not.We didn’t know if the Trace system wasn’t actually ableto handle the 65 amps, or whether the startup load wasgreater than initially specified.

Geoff Levin at Trace was great. He helped us balancethe inverter loads, and started us on the road to solvingthe inverter tripping problem. Though Trace sent theirPower Tracer line logger to document AC runningloads, we still failed to locate the problem. However,ECS wrenches with the Fluke 87 series III multimetersaved the day.

Two Fluke 87s set at micro surge time for the AC ampmeters both agreed that the compressor sometimesdrew 132 amps on startup—way above factory

specifications. Problem solved—theAC contractor changed thecompressor to two dual-stagesystems, and the tripping problemended.

As a matter of caution, wrenchesshould be extremely careful tocompare any inverter manufacturer’sstated continuous and surge ratingsto “real situations.” Many invertermanufactures, including Trace, oftenlist both continuous and surgeratings in kilowatts (KW) instead ofvolt-amps (VA).

An inverter’s continuous power andsurge power ratings might be listedas “5,500 watts continuous; 9,300watts surge.” More accurate ratingsare not in watts but in volt-amps.This recognizes that the 5,500 watt

rating is, at best, only for 5,500 watts of resistance load(such as fifty-five 100 watt light bulbs).

The inverter may be required to deliver 6,850 watts topower inductive loads for a motor requiring 5,500 watts.Motors put an electromotive force or resistance backinto the line, which reduces available wattage andrequires additional power at the front end. Meters onthe Trace SW5548 only accurately read AC resistanceloads. The motor power factor typically requires 25percent more power from the inverter to meet the loadneeds.

Net MeteringGeorgia’s new net metering law passed on April 28,2001, and links customer-generated power with greenpricing. This paves the way for a new relationshipbetween the utility and customer-generated power.

At peak periods, a customer with up to 10 KW ofrenewable energy capacity for residential applicationscan get 15 to 20 cents per KWH or more until capacityreaches 0.2 percent of the utility system’s peak. Thismeans that Steve Davison can sell at 15 to 20 centsduring the day, and purchase the power back at night at8 cents per KWH if needed.

The Davisons are using power from this system to buildtheir new home. The entire home is being built usingsolar-electric power, with any surplus going to the grid.Steve and his wife Debra are some of the firstresidential homeowners in Georgia to enjoy watchingtheir meter run backwards.

Solar PhilosophyThere is great diversity of people who support solar

Efficiency, load shedding, and solar like this pool heater, were all important for the PV system to meet the projected loads.


Photovoltaics

equipment with their wallets rather than rhetoric. Theircommon belief is that money is given value by howresponsibly it is used. The docks along the southerncoastal states are filled with yachts owned by peoplewith different philosophies. Many southern estates alsohave two or three expensive status cars that cost asmuch as or more than the Davison PV system.

Steve, who made his money with a variety of inventionsand businesses, chose to spend his earnings as a solarpioneer, creating New Tara as an example and achallenge to upscale estate and plantation owners ofthe south. Steve’s solar-electric system is much largerand more complex than most. But his beliefs aboutgreen and renewable energy are the same as those ofpeople with smaller systems we all read about in HomePower.

His challenge with New Tara was to break the southernculture of consumerism that places emphasis onspending money for status rather than for responsiblesocietal value. Making “real value” purchasing the newresponsible status symbol of the wealthy could go along way toward protecting the earth and its resources.This is especially relevant for others in financialpositions like the Davisons, who can easily affordsystems like this.

We need enthusiastic supporters of solar energy fromevery walk of life, willing to be examples to their friendsand neighbors. In my twenty-three years of solarcontracting experience, I have learned one thing:politicians and utility companies don’t dictate socialvalues—people do.

Only a change in the majority mindset can reduce theacceleration of global climate change overtaking us.What takes place in the next thirty years could haveirrevocable implications for us all. Time is running out—the earth’s ecosystems and climate are rapidlychanging.

We all know that the end of the oil age is in sight. If youare less than twenty years old, you will probably live tosee the last oil wells go dry—sometime between 2040and 2080.

The renewable energy age is beginning out ofnecessity. We are starting our upward, renewableacceleration just as the oil industry plunges downwardto the end of its ride. Steve Davison’s single crystalsolar modules may last into the next century—manyyears after the end of the oil age.

AccessTom Lane, Energy Conservation Services, 6120 SW13th St., Gainesville, FL 32608 • 352-377-8866

Fax: 352-338-0056 • [email protected]

Linda Tozer, Florida Solar Energy Research andEducation Foundation,145 Wekiva Springs Road, Suite187, Longwood, FL 32779 • 407-774-9939Fax: 407-774-9941 • [email protected] • Consultation

Ken Fonorow, Florida HERO, 15220 NW 5th Ave.,Newberry, FL 32669 • Phone/Fax: [email protected] • www.floridahero.com • BuildingScience Consultant

Jeff Randall, Direct Power and Water Corp., 4000-BVassar Dr. NE, Albuquerque, NM 87107 • 800-260-3792or 505-889-3585 • Fax: [email protected] • www.directpower.comPV racks

Jim Jackson, On-Site Power, Inc., 2301 NE 17th Pl.,Suite 103, Ocala, FL 34470 • 888-423-1090 or 352-671-1090 • Fax: [email protected] • www.on-sitepower.comDesigner of generator controls

John Ault, 2323 NW 182nd St., Newberry, FL 32669352-472-5716 • [email protected] and troubleshooter

Siemens Solar Industries, PO Box 6032, Camarillo, CA93011 • 800-272-6765 or 805-482-6800Fax: 805-388-6395 • www.siemenssolar.com • PVs

Jamie Dempsey, Energy Conservation Services, 6120SW 13th St., Gainesville, FL 32608 • 352-377-8866www.ecs-solar.com • Foreman and constructionsupervisor

Roger Locke, Hutton Communications, 775 TiptonIndustrial Blvd., Suite F, Lawrenceville, GA 30045877-896-2806 or 770-963-1380 • Fax: [email protected] • www.huttonsolar.comEquipment and parts

International Energy Systems Corporation, PO Box588, Barrington, IL 60011 • 800-927-0419 or 847-381-0203 • Fax: 847-381-3997 • [email protected] PV-powered roof fans

Aquatherm Industries, 1940 Rutgers university Blvd,Lakewood, NJ 08701 • 800-227-7657Fax: 732-905-9899 • [email protected] • Solarpool heating equipment

No Power? No Problem!There is more to a working renewableenergy system than a cheap deal on apile of hardware.

We Provide:Complete service.We do solar, wind, microhydro andpumping systems. Load analysis, site survey, systemdesign, sales, installation, user training, and techsupport long after the warranties expire.We live onrenewable energy, have 20 years of experience, andhave established over 500 systems.We specialize inNEC ® compliant, safe systems that will make yourElectrical Inspector smile!

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ElectronConnectionElectronConnection


olling blackouts havebecome a regularoccurrence for many

electric utility customers in California.Drought conditions in much of the PacificNorthwest have radically reducedhydroelectric generation utilized up anddown the West Coast. As a result, thestates of Oregon and Washington face asteadily increasing probability of beingdragged into California’s energydebacle. Lack of both transmission andgeneration capacity in Illinois, Michigan,Delaware, and New York may plague theresidents of these states with blackoutsin the near future.An inverter/battery-based uninterruptible power supply(UPS) will provide blackout-proof power to your home.This system will keep your electric appliances up andrunning during utility blackouts caused by acts of naturesuch as storms, or by acts of man such as utility

irresponsibility. This article provides all the specifics fora basic UPS system. We call this blackout buster the“Midnight Special.”

The system is both modular and expandable—a largercapacity battery bank or renewable energy inputs caneasily be added to the system. The basic MidnightSpecial costs about US$6,000, and that includesprofessional installation.

System OverviewWe chose a Trace SW series inverter as the centralcomponent of this UPS system. An inverter-based gridbackup system uses utility power, when it’s available,to charge a battery bank. When a blackout occurs,selected loads are automatically transferred to theinverter. The inverter’s main job is to take a battery’sl inear DC waveform and create a digitalrepresentation of an AC sine wave. This is thewaveform that your household appliances aredesigned to run on.

During a power outage, the inverter uses the energystored in the batteries to power household loads. Whenthe grid comes back online, the loads are automaticallytransferred back to grid power. Then the inverter’sbattery charger goes to work and recharges thebatteries, so the system is ready to go when the nextblackout rolls around.

Which one of these houses is yours? Blackout protection lets you decide when the lights go out.

Joe Schwartz& Richard Perez©2001 Joe Schwartz & Richard Perez

Let The Midnight Special Shine Its Light On Me…

R


System—Blackout Protection

The LoadsThe load table (page 36) lists the appliances weselected to be powered by this UPS system. Bothessential and desirable loads have been included. Thesystem is designed to support up to a 4 KWcontinuous load. It will supply about 6,500 watt-hoursof energy per day in a normal appliance usagescenario. This system will keep the lights on, thefridge/freezer operating, the communication gearrunning, and still have power left over to vacuum thefloors and do the wash.

The system is designed to power these loads for aperiod of 24 hours—far longer than the average utilityblackout. For power outages lasting several days, anengine-generator or photovoltaics (PVs) can be addedto the system to recharge the batteries and energizethe system.

This system is not compatible with large thermal loadspowered by electricity. It is not designed to run electricstoves, electric water heaters, electric space heating,heat pumps, or central air conditioning. All these loadsare very big energy consumers, and beyond thecapabilities of this system.

The PartsThis system uses standard off-the-shelf renewableenergy equipment—the same inverter, batteries,instrumentation, and safety gear found in many off-gridhomes. The renewable energy equipment selected forthis system has been proven to be efficient andreliable over years of use in thousands of off-gridhomes in the U.S.

The specified components are UL listed for fire safety—just like the rest of the appliances in your home. Thecost table (page 38) gives a list of the equipment usedin this UPS system. Estimated prices for the equipmentand professional installation are included.

Inverter/Battery ChargerA Trace SW4024 inverter creates standard 120 VAC, 60Hz electricity from the energy stored in the batterybank. Trace SW series inverters are the mostcommonly used inverters in off-grid and grid backupsystems. The model specified for this system is theSW4024. It has a 24 VDC input and a 4,000 VAAC output.

Two other 60 Hz Trace SW series inverters areavailable—the SW4048 and the SW5548. Theseinverters have a 48 VDC input voltage and 4,000 VAand 5,500 VA output respectively. The surge capacity ofall three models is 78 amps at 120 VAC. Export modelsare also available with 230 VAC, 50 Hz outputs.

Trace SW series inverters have an onboard, 60 ampAC transfer switch. When grid electricity is present, thetransfer switch routes utility power directly to householdloads. When a power outage occurs, the loads areautomatically transferred to the inverter/battery system.Depending on the nature of the grid failure, this transfermay be noticeable—the lights may momentarily dim.But the transfer time is typically fast enough to keepcomputers running during most grid failures.

A Trace SW4024 inverter uses three transformers tocreate an AC waveform to run your appliances. TheSW4024 is also designed to run these transformersbackwards to charge your batteries. In this mode, thetransformers are capable of producing 120 amps at 24VDC for charging your batteries. The charge rate isuser programmable, and the inverter automaticallyreduces the charge rate as the batteries become full.

This inverter interfaces gracefully with grid power, andis equally at home on the grid or off. And best of all,renewable energy sources can be added to this system.PVs, a wind generator, or a microhydro turbine cansupply all the power your home needs. The SW series

The Midnight Special’s system components—sealed Concorde 6 volt, 220 amp-hour,absorbed glass mat (AGM) batteries (left);TriMetric amp-hour meter (center); and Trace SW4024

sine-wave inverter with AC disconnect/bypass box (right) and DC disconnect box (far right).

Let The Midnight Special Shine Its Ever-Lovin’ Light On Me!



inverter is even designed to spin your utility meterbackwards and place your surplus renewable energy(RE) on the utility grid for your neighbors to use.

Trace SW series inverters require programming oncethey're installed. The settings table showsrecommended set points for the 440 AH battery bankspecified for the Midnight Special. Regulation set pointsfor both sealed AGM and flooded lead acid batteries areincluded.

BatteriesWe selected 6 volt, 220 amp-hour, sealed Concordeabsorbed glass mat (AGM) batteries for this UPSsystem. Sealed batteries are becoming more and morepopular, especially in on-grid systems where thebatteries are typically kept at a full state of charge.

Sealed batteries are very userfriendly compared to standardflooded lead-acid cells. They aremaintenance free, so you neverneed to add water. All batteriesexperience self-discharge, a gradualloss of energy within the battery. Butdifferent battery types experiencedifferent rates of self-discharge. Newsealed batteries have about onetenth the rate of self-discharge(between 1 and 3 percent a month,depending on temperature) offlooded lead-acid batteries.

Sealed batteries are safer. They donot produce large quantities ofhydrogen gas like flooded lead-acidcells. So they don’t need to bevented to the outside. But theyshould sti l l be located in acontainment. You never want toleave battery terminals exposed tokids, dropped wrenches, etc.

No maintenance, no gassing, lowself-discharge—why use anythingelse? Well, Concorde AGMs costroughly 40 percent more thanflooded lead-acid cells. But if youhave the cash, Concorde AGMs area great way to go.

It’s important to note that sealedbatteries may be permanentlydamaged by battery voltages higherthan manufacturer specifications.Concorde specifies voltages nohigher than 14.4 VDC for a 12 VDCnominal system. So the batteries in

our 24 VDC UPS system should never be chargedhigher than 28.8 VDC. The SW4024 inverter allows youto set both bulk and float voltages, so you can maintainthe batteries at the proper regulation voltage.

The 440 amp-hour battery bank for this system is sizedfor the intermittent use of the appliances listed in theload table. This is a minimal battery bank compared tothe full output capabilities of the SW4024 inverter. Asthe inverter powers these selected loads, batteryvoltage will sag. This will happen when loads with alarge startup surge (like the vacuum cleaner) areturned on.

Most modified square-wave inverters are not voltageregulated. So as the battery voltage drops, so does theAC output voltage. This isn’t the case with SW series

INVERTER SUPPLIED 120 VAC APPLIANCE POWER CONSUMPTION ESTIMATE

Midnight Special Date:Your HouseSunny, California USA

AC Watt-hrs. Used Daily 6512

Please note: this is an estimate and is only as good as the information supplied.

All Appliances on the list below are powered by 120 VAC from the inverter

Run Start Hours DaysNo. Inverter Powered Appliance P? Watts Watts /Day /Week W-hrs/day %

1 19 cu ft refrigerator/freezer 1 140 240 10.00 7.00 1400.0 21.11%

1 Computer monitor 1 90 200 8.00 7.00 720.0 10.86%

1 Solar DHW system 1 75 75 8.00 7.00 600.0 9.05%

1 Computer 1 60 120 8.00 7.00 480.0 7.24%

6 Fluorescent lights 1 15 15 5.00 7.00 450.0 6.79%

1 Laser printer 1 700 1200 0.50 7.00 350.0 5.28%

1 Television set 1 75 200 4.00 7.00 300.0 4.52%

1 Stereo 1 25 25 9.00 7.00 225.0 3.39%

1 Washing machine 1 250 500 1.25 5.00 223.2 3.37%

1 Microwave oven 1 800 1200 0.25 7.00 200.0 3.02%

1 Vacuum cleaner 1 1350 2700 0.50 2.00 192.9 2.91%

1 Video cassette recorders 1 40 40 4.00 7.00 160.0 2.41%

1 Fax standby 1 5 5 24.00 7.00 120.0 1.81%

1 Cordless telephone 1 4 4 24.00 7.00 96.0 1.45%

1 Ni-Cd battery recharger 1 20 20 6.00 3.00 51.4 0.78%

1 Fax/Copier 1 40 40 1.00 5.00 28.6 0.43%

1 Sewing machine 0 80 160 4.00 1.00 45.7 0.69%1 Blender 0 350 700 0.05 7.00 17.5 0.26%

1 Coffee grinder 0 50 150 0.05 7.00 2.5 0.04%

***************************************************************************************************************Inverter AC W-hrs Consumed Daily 5663 w15% Invert Ineffic.= 6512.2

Largest Appliance Wattage 1350

Largest Appliance Surge Wattage 2700

Inverter Priority Wattage 3764

08/01/01

Typical Load Table (From Energy Master Spreadsheet)



inverters, which regulate AC output voltage (120 VAC+/- 3%). SW series inverters have a user programmablelow battery voltage cut-out. They also have anadjustable low battery cut-out delay. This keeps theinverter online when battery voltage dips with thestartup of motors with a large surge.

The smaller the battery bank, the greater the voltagedepression, and the harder the batteries are worked. Asmall battery bank also means deeper discharges whenthe grid fails and the batteries are cycled. But in UPSsystems, small battery banks are common. Thebatteries spend most of their lives at a full state ofcharge, and are only cycled intermittently.

In an off-grid system, the batteries are cycled on a dailybasis. A 700 to 900 amp-hour battery at 24 VDC is agood minimum off-grid battery capacity in relation to theoutput of an SW4024 inverter. The standard batterybank supporting an SW4024 in an off-grid system is1,000 to 1,200 amp-hours at 24 VDC. A larger batterybank means higher voltage under load. And because ofthe increased capacity, the batteries are cycled lessdeeply, increasing battery longevity.

Battery longevity is directly related to how well thebatteries are maintained. The major causes of earlybattery death are chronically undercharging orovercharging them, deeply discharging them, and notadding water if you’re running flooded lead-acid cells. Aset of properly maintained batteries, adequately sizedfor a given system, can be expected to last ten years ina grid backup application. Depending on how often thebatteries are cycled, a significantly longer batterylifespan can be expected.

InstrumentationA critical piece of equipment for any battery-basedsystem is an amp-hour meter. This meter comparesthe amps coming into the battery from the chargingsources to the amps going out to the loads. An amp-hour meter is the only accurate way to monitor thestate of charge (SOC) of your batteries. It is also veryconvenient, and accessible to non-technical users.The meter displays battery SOC as a percentage oftotal capacity. Just like the fuel gauge in your car, aquick glance at the meter tells you your batteries’SOC.

Midnight Special

Power InFrom Utility Grid

ON

ON

OF

FO

FF

60

60

AC In

AC Out

AC Disconnect/Bypass Box: 60 amp breakers

Inverter: Trace SW4024, sine-wave;120 VAC 60 Hz in/out from utility,

24 VDC in from battery bank

AC Mains Panel:240 VAC, 24 circuit box

EarthGround

Instrumentation:TriMetric 2020 amp-hour meter

Battery Bank: Eight sealed Concorde 6 volt, 220 amp-hour, absorbed glass mat (AGM) batteries. Wired series/ parallel for 24 volts, 440 amp-hours.

DC Disconnect:Trace, with

250 amp DCrated breaker

Subpanel:120 VAC fromUPS or grid.

Twelve circuit box. To all loads backed up by

this UPS system.

Power Conversion Center

60 ADC Disconnect /

Overcurrent Module

28.8

2 Afuse



Three different brands of amp-hour meter are available:Bogart Engineering’s TriMetric, Xantrex’s Link 10,and the Trace TM500. All three of these meters displaybattery SOC and other system information.

In this intermittent, grid backup application, an 80percent depth of discharge (DOD) is acceptable. Wenever recommend discharging your lead-acid batteriesby more than 80 percent (20% SOC). Doing so willgreatly decrease your battery bank’s longevity. Withouta battery amp-hour meter, you won’t know how deeplyyou are discharging your batteries.

In an off-grid system, batteries are cycled on a dailybasis. In that case, a 25 percent daily depth ofdischarge is good threshold to shoot for. Remember,batteries like to be at a full state of charge. The lessdeeply you cycle them, the longer they’ll last.

DC Safety GearYour battery bank has the potential to deliver tens ofthousands of amps if a direct short ever occurred. Thisis a fire hazard and a potentially life-threateningsituation. So just like the circuits in your house, youwant to make sure to have a fused disconnect orbreaker between the battery bank and the inverter.Since this breaker is on the low voltage DC side of thesystem, a high current DC-rated breaker is required.

Trace manufacturers a DC250 enclosure that houses a250 amp DC-rated breaker. This provides overcurrentprotection between the inverter and batteries. It also

makes it possible to electricallyisolate the inverter from the batteriesif inverter servicing is ever required.

Interfacing with the Grid—The SubpanelThe maximum continuous outputcurrent from a Trace SW4024 is 33amps at 120 VAC. Your home’smains panel is probably a 100 amp,200 amp, or even larger service. Soit’s quickly apparent that a singleinverter can’t handle all the loads ina typical, on-grid household.

Usually, only certain loads aredeemed important enough to requirea backup power source. You need tosurvey the appliances in your homeand decide which ones you wantdedicated to your UPS system. Thetotal appliance load must be withinthe inverter’s output rating. In thiscase, that limit is 33 amps at 120VAC (4,000 watts) continuous.

The next step is to identify the circuits that power theappliances requiring backup power. Circuit locations areusually listed on the inside of the cover of your mainspanel. Once these circuits have been identified, they arepulled from the AC mains panel and rerouted to a newAC subpanel. Now you have a dedicated breaker panelfor loads requiring an uninterruptible power supply.

In our case, the output of the inverter is run through a60 amp breaker and on to the subpanel. In addition,grid power for battery charging must be run via a 60amp breaker from your mains panel to the inverter. Bothof these 60 amp breakers are included in the inverterbypass switch, which is housed in a separateenclosure, typically mounted above the inverter.

Inverter Bypass SwitchYou always want to include an inverter bypass switchin a battery based, utility intertied system. You recallthat in this UPS system, when grid power is available,it is routed directly to the dedicated AC loads by wayof the inverter ’s internal transfer switch. Veryoccasionally, an inverter needs to be removed forservice. When the inverter is removed for repair, so isthe onboard transfer switch. This isolates thededicated subpanel from the mains panel. That blacksout all the loads powered via the subpanel, which isdefinitely not the desired effect.

Without the inverter bypass switch, you would have totemporarily rewire the subpanel directly to the mainspanel. Then you would have to switch the wiring back

Typical Midnight Special Costs (From Energy Master Spreadsheet)RENEWABLE ENERGY SYSTEM HARDWARE COST ESTIMATE

Midnight Special Date:

Your house

Sunny, California USA

Power Consumption 6632.204 Watt-hours/day

Initial Cost Estimate $5760.00

No. Item Description Type Unit Price Item Total % of Cost1 Trace inverter SW4024 $3,495.00 $3,495.00 54.69%8 Concorde batteries B-PVX6220 $179.00 $1,432.00 22.41%

8 Installation labor per hour estimate $50.00 $400.00 6.25%

1 Inverter/battery disconnect DC250 $329.00 $329.00 5.14%

1 Battery amp-hour meter TriMetric $200.00 $200.00 3.12%

10 Battery/inverter cables $180.00 $180.00 2.81%

1 Misc. wire and fittings estimate $100.00 $100.00 1.56%

1 Trace SW conduit box SWCB $94.00 $94.00 1.47%

1 AC subpanel 8 circuit $80.00 $80.00 1.25%

1 Inverter bypass switch Sq. D $80.00 $80.00 1.25%

Total Initial Hardware Cost Estimate $6,390.00

08/01/01



again when the inverter was re-installed. If you’re notdoing the work yourself, this would mean two trips by alocal electrician. A bypass switch eliminates thispotentially expensive headache.

A three circuit Square D load center (model numberQO403L60NS, with butterfly switch), one single pole 60amp QO breaker, and one double pole 60 amp QObreaker are the parts that make up the bypass switch.At retail, this setup costs about US$80. The bypassswitch allows you to throw one switch and route ACpower from the mains panel directly to the subpanel.The breakers in the bypass switch also serve asovercurrent protection between the mains panel and theinverter, and between the inverter and the subpanel.

Non-Grid Power SourcesThe local utility isn’t the only source of electricity. Asmany off-grid HP readers can testify, there are manyways of making electricity that don’t involve the utility.The Midnight Special is designed to handle them all.

AC GeneratorsIf a utility blackout begins to stretch out for days, youneed to come up with another power source torecharge the batteries and energize the system. Themost common option is an engine-powered generator.Trace SW series inverters are designed tosimultaneously manage both utility grid and engine-generator inputs. User programmable setpoints allowthe use of most common generators.

Trace SW series inverters can also be programmed toautomatically start generators based on either time ofday or battery voltage. This sample system does notinclude a generator, since it’s designed to power thespecified loads for 24 hours. The majority of grid failurescan be weathered by an appropriately sized batterybank.

Off-grid homes powered solely by an engine generatorwill also benefit greatly from the addition of aninverter/battery system. Generator-to-loads directsystems are extremely inefficient to run. Electricityproduced by an engine generator costs aboutUS$0.60 KWH.

More often than not, the generator will be operating at afraction of its full output. Running a 10 KW generator topower a couple of lights and a TV is a tremendouswaste of fuel. And you have to listen to the blasted thingwhenever you want to turn on a light! Adding an inverterand batteries to the system will reduce generator runtime, noise, and fuel costs by 80 to 90 percent.

Photovoltaics, Wind, & MicrohydroSince the gear used in this system is standard stuff, itcan switch from a steady diet of grid power to a

pollution-free diet of renewable energy. You can addPVs, wind power, microhydro, or a combination. Thiswill make the system (and your home) energy selfsufficient. Of course, RE resources are site specific.Most suburban homeowners don’t have a streamcascading down their back yard, and wind turbines aretough to site in town.

If you have any surplus RE generated at your home, itcan be placed on the grid for others to use. We

Need a

Larger UPS

System?

Or a Smaller

One?Sometimes backup power demands are higher thanthe rated output of a single inverter. With theaddition of an interface cable, two Trace SW seriesinverters can be stacked in either a series or parallelconfiguration for increased output.

For example, two series-stacked SW4024 invertershave a 120/240 VAC split phase output. Thewaveforms of the two inverters are 180 degrees outof phase—like the utility lines coming into yourhouse. This configuration gives you two 4,000 VAlegs, and allows you to run 240 VAC appliances.Two SW inverters can also be stacked in parallel for8,000 VA of single phase, 120 VAC output.

Larger systems will require a larger battery bank.Always start with a survey of the loads you need toback up, and the number of minutes or hours youneed to run them. In a grid backup application, yourbattery bank should be sized for a maximumdischarge of 80 percent.

Just want to back up your computer? Off the shelfcomputer UPS systems may be your best bet. Wantto back up your computer, a couple of lights, andyour stereo? Calculate the total load you want topower and how long you want to power it. Thenchoose an appropriate battery bank capacity basedon an 80 percent depth of discharge. Exeltechmanufacturers small true sine-wave inverters.Several models are available with AC outputs from125 watts to 1,100 watts. These inverters supplyhigher quality power than the utility grid. And you’rethe one to decide when they get shut down!



estimate that about US$8,000 worth of PV and a largerbattery will make this system capable of deliveringabout 6 KWH per day. This will run the loads listed inthe table, on a site with 5.3 average sun hours per day.

A System with a FutureConsidering the increasingly unreliable nature of utilitygrids, this system offers you a future where the lightsare always on. If a storm brings down the power linesand puts out the lights, this system can bring themback. If the local utility gets irresponsible and shuts offthe power because they can’t make a profit or supplythe demand, your lights will still be on. And then there isthe tantalizing possibility of adding solar, wind, ormicrohydro energy to this system. The Midnight Specialis a blackout buster with a clean and green future.

AccessJoe Schwartz, Home Power, PO Box 520, Ashland, OR97520 • 541-512-0201 • [email protected]

Richard Perez, Home Power, POBox 520, Ashland, OR 97520530-475-3179 • Fax: [email protected]

Bogart Engineering, 19020 Two BarRd., Boulder Creek, CA 95006831-338-0616bogart@bogartengineering.comwww.bogartengineering.comTriMetric AH meter

The Energy Master Spreadsheet isavailable for free from the Downloadsection at www.homepower.com oron the HP Solar CD-ROMs

Concorde Battery Corp., 2009 SanBernardino Rd., West Covina, CA91790 • 800-757-0303 or 626-813-1234 • Fax: [email protected]

Exeltech, 2225 East Loop 820 N, Ft.Worth, TX 76118800-886-4683 or 817-595-4969Fax: [email protected] • Inverters

Surrette Battery Company Limited,PO Box 2020, Springhill, NS B0M1X0 Canada • 800-681-9914 or

902-597-3767 • Fax: [email protected] • www.surette.com • Flooded lead-acid batteries

U.S. Battery,1675 Sampson Ave., Corona CA 92879800-695-0945 or 909-371-8090 • Fax: [email protected] • www.usbattery.com

Trojan Battery Company, 12380 Clark St., Santa FeSprings, CA 90670 • 800-423-6569 or 562-946-8381Fax: 562-906-4033 • [email protected] • Flooded lead-acid batteries

Xantrex Technology Inc., Distributed Residential andCommercial Markets, 5916 195th St. NE, Arlington, WA98223 • 360-435-8826 • Fax: [email protected] • www.xantrex.comTrace inverters, E-Meter, Link 10 & TM500 AH meters,and DC250

Midnight Special Inverter Settings

RecommendedMenu Heading Menu Item Setting

For 8 Concorde Sealed AGM Batteries, 440 AH at 24 VDC

Inverter Mode - 1 Set Inverter SRCH (search)

Time of Day - 6 Set Hr/Min/Sec

Inverter Setup - 9 Set Grid Usage FLT (float)

Set High Battery Cut-Out VDC 29 VDC

Set Search Watts 16 watts

Battery Charging - 10 Set Bulk VDC 28.8 VDC

Set Absorption Time 1:00 Hr.

Set Float VDC 26.8 VDC

Set Max Charge Amps AC 20 Amps AC

Set Temperature Compensation Lead-Acid

For 8 Flooded Lead-Acid Batteries, 700 AH at 24 VDC

Inverter Mode - 1 Set Inverter SRCH (search)

Time of Day - 6 Set Hr/Min/Sec

Inverter Setup - 9 Set Grid Usage FLT (float)

Set High Battery Cut-Out VDC 32 VDC

Set Search Watts 16 watts

Battery Charging - 10 Set Bulk VDC 29.6 VDC

Set Absorption Time 1:00 Hr.Set Float VDC 26.8 VDCSet Max Charge Amps AC 20 Amps ACSet Temperature Compensation Lead-Acid


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Trojan Battery


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ot water represents the secondlargest energy consumer inAmerican households. A typical

80 gallon (300 l) electric hot water tankserving a family of four will consumeapproximately 150 million BTUs in itsseven year lifetime. This will costapproximately US$3,600 (at US$0.08per KWH), not accounting for fuel costincreases. Then it will be replaced byanother one just like it. Hmm. Maybe weshould rethink this...An investment in a solar water heating system will beatthe stock market any day, any decade, risk free. Initialreturn on investment is on the order of 15 percent, tax-free, and goes up as gas and electricity prices climb.Many states have tax credits and other incentives tosweeten those numbers even more. What are wewaiting for? Forget the stock market. If you haveinvested in a house, your next investment should be insolar hot water.

In this article I’m going to cover the most commonoptions for solar water heating, basic principles ofoperation, and some historical perspective on what hasworked and what has not.

A Checkered Past, A Bright FutureSolar thermal’s past is a good example of why everyone should be skeptical of governmentinvolvement in energy. Lucrative federal and state taxcredits for solar energy were initiated under PresidentJimmy Carter in the ‘70s, and abruptly eliminated underPresident Ronald Reagan in 1985. This dealt the solarindustry a devastating “one-two punch” from which itstill has not recovered.

The intention was to stimulate sales for solar thermalsystems. But the tax credits resulted in an aggressivepromotion of tax credits rather than solar energy. Theinfant industry was overwhelmed to meet the demand.The demand vanished when tax credits wereeliminated, and a majority of solar thermal companieswent out of business. Thousands of orphaned solarthermal systems were left behind looking for a servicetechnician.

The solar thermal industry has been purged of the taxcredit telemarketers and overnight experts. Today’ssolar thermal industry includes reliable, efficient

Ken Olson©2001 Ken Olson

Solar hot water is one of the most immediately cost-effective uses of renewable energy.


Solar Hot Water

products and well-seasoned professionals who haveseen it all. Solar hot water is one of the bestinvestments you can make for your house and for theenvironment.

First Things FirstThe best savings in hot water come from no cost or lowcost options. Before you tackle solar hot water, takethese steps:

• Turn the thermostat down. Many water heaters areset to between 140 and 180°F (60 and 82°C). Seehow low you can go. Try 125°F (52°C) for starters. Ahot tub is 106°F (41°C). How much hotter do youneed?

• Wrap the water heater with insulation. Insulated waterheater “blankets” are usually available where waterheaters are sold. (Be careful with natural gas orpropane fired water tanks. They use an open flame toheat the water. You need to provide a space for air atthe bottom of the tank, and at the top where the flueexits the tank. Safety comes before efficiency!)

• Fix those drips. They may not look like much, but theyare a constant and persistent drain on your waterheating load, and they waste water too.

• Use flow restrictors and faucet aerators to reduceyour hot water consumption.

• Find other ways to use less hot water. Wash only fullloads of clothes and dishes.

• Insulate your hot water pipes.

How Large a Solar Hot Water System Do You Need?Hot water usage in the U.S. is typically 15 to 30 gallons(55–110 l) per person per day for home use. Thisincludes primarily bathing, clothes washing, anddishwashing. But your commitment to efficiency has alot to do with your actual usage.

The hot water tank is usually sized to handle one day’sworth of consumption. So for a household of four, itwould be reasonable to use an 80 gallon (300 l) tankbased on daily hot water requirements of 20 gallons (75 l) per person per day.

Smitty and Chuck at AAA Solar in Albuquerque haveput forth generally accepted rules of thumb for solarthermal collector sizing based on your climatic region:

• In the Sunbelt, use 1 square foot (0.09 m2) ofcollector per 2 gallons (7.6 l) of tank capacity (dailyhousehold usage).

• In the Southeast and mountain states, use 1 squarefoot of collector per 1.5 gallons (5.7 l) of tank capacity.

• In the Midwest and Atlantic states, use 1 square footof collector per 1.0 gallon (3.8 l) of tank capacity.

• In New England and the Northwest, use 1 square footof collector per 0.75 gallon (2.8 l) of tank capacity.

Based on these rules of thumb, a household of four withan 80 gallon (300 l) tank will need approximately 40square feet (3.7 m2) of collector in Arizona, 55 squarefeet (5.1 m2) of collector in South Carolina, 80 squarefeet (7.4 m2) of collector in Iowa, and 106 square feet(9.8 m2) of collector in Vermont.

Of course, these are big ballpark calculations that willbe affected by your incoming water temperature, hot

Collector Back

Insulation:High temperature

rigid foam

Inlet Outlet

Manifold

Absorber Plate

Glazing

Valve

Check Valve: One-way Flow

Pump

Antifreeze (propylene glycol): Cooler

Antifreeze (propylene glycol): Hotter

Potable Water: Cooler

Potable Water: Hotter

Temperature Sensor: With wire

Power Wire: Not always shown

Key to Plumbing Symbols

A Typical Solar Flat Plate Water Heater


Solar Hot Water

water temperature setpoint, actual usage, and theintensity of the solar resource at your site. You shouldgenerally expect that this will give you 100 percent ofyour hot water in the summer and about 40 percent ofyour hot water year-round.

Your Choices—An OverviewThe type of system you choose will depend mostly onyour climate. Freeze-free environments allow forsimple, low cost designs. A batch heater uses a storagetank as a collector. A direct pump system circulateswater from a collector to a storage tank. A thermosiphonsystem requires no pump for circulation, just the naturalflow of gravity.

Most systems will require some measure of freezeprotection. Drainback and closed loop systems withantifreeze and heat exchangers are the best choice forfreezing locations. The extra parts increase cost andreduce efficiency, but since one frozen moment can turninto a disaster, it’s worth the cost.

Direct pump recirculation systems, which circulate hotwater through the collector, are often used wherefreezing is an infrequent occurrence. That’s a riskystrategy. Draindown systems, designed to drain waterfrom the collectors to avoid freezing, were the mostproblematic of system designs. Many were removed orconverted. Phase change systems, which in theorycould collect heat at night using a refrigerant, nevermade it into the mainstream of commercial viability.Many of the lessons learned in solar hot water arepresented in a publication Solar Hot Water Systems:Lessons Learned, by Tom Lane (see Access).

Solar Batch HeatersThe KISS (keep it simple, stupid) rule applies to solarheating. The batch water heater is the simplest of solarhot water systems. Once affectionately referred to asthe breadbox water heater by the do-it-yourself (DIY)community, it has become known as the ICS (integratedcollector and storage) water heater in the commercialindustry. Its simple design consists of a tank of waterwithin a glass-covered insulated enclosure carefullyaimed at the sun.

Cold water, which normally goes to the bottom of yourconventional water heater, is detoured to the batchheater first. There it bakes in the sun all day long, and ispreheated to whatever temperature the sun is able toprovide. Water only flows when used. House waterpressure causes the supply of new cold water to flow tothe inlet of the batch heater, the lower of the two ports.

Simultaneously, the hottest water exits from the higherport. It flows to the input of the existing water heater,which now serves as a backup to finish the heating job

as required. Solar preheated water has become thecold water input to the existing water heater. You savewhatever the sun is able to provide. And you still get allthe hot water you ask for—it’s that simple.

Bypass ValvesA solar bypass is a series of three valves that allow youto bypass the existing water heater. You can shut itdown when the solar collector will do the job alone,such as during summer months or utility blackouts. Thisis a manually operated configuration; just close off theinlet and outlet valve to the existing tank and open thecenter valve. This allows hot water to pass directly fromthe solar batch heater to the house.

Valve:Open

Valve:Closed

Drain Valve:Closed

StorageTank:

Backupheater

HotIn

HotOut

SolarBypass:

See detail

Batch Heater: Tank in insulatedbox with solar-oriented glazing

TemperingValve:

Limits hot tohouse

Hot toHouse

Cold toHouse

ColdSupply

Temperature / PressureRelief Valve

Temperature /Pressure

Relief Valve

Batch Heater System

A 40 gallon batch heater.


Solar Hot Water

Caution! These systems produce very hot water! Atempering valve is your protection from being scalded atthe tap. You will regularly see temperatures in excess of160°F (71°C) in summer months, which is much hotterthan you are accustomed to getting from yourconventional thermostatically controlled water heater.The tempering valve limits the temperature delivered tothe tap by mixing in cold water as necessary.

A pressure temperature relief valve (PTRV) must beinstalled at the hot water outlet of the batch heater incase temperatures or pressures become excessive.You will find one of these valves installed on everyconventional hot water tank too. It is a safety measurerequired by code. This valve only operates in anemergency, and is often replaced if it opens.

Who Can Use a Batch Heater?Batch heaters are most appropriate for two to fourperson households (30 to 40 gallon (110–150 l) dailyhot water requirement) in climates where freezing isinfrequent. Their size is generally limited because thetank is built into the collector.

Multiple collectors can be installed in series for largercapacities. The outlet of the first collector becomes theinlet of the second in order to deliver highertemperatures. Before you put too many on your roof,consider that a 40 gallon (150 l) batch heater will weighapproximately 500 pounds (225 kg).

Some batch heaters have survived the coldest ofwinters with freeze-free performance because the largemass of the water tank is quite freeze tolerant. Butplumbing lines to and from the tank are very vulnerable.You can make it work with a special selective surfaceon the tank, a well-insulated, double glazed collector, awhole lot of well-sealed pipe insulation (try R-30 orbetter), heat tape on the pipe, and good karma.

Are you arrogant enough to tempt Mother Nature to turnyour water heater into a frozen fountain? Or are youprepared to drain the collector seasonally? If not, thissystem is not recommended for climates that freezeregularly.

Separate Collector & StorageThe simple design of a batch heater compromises theeffectiveness of collector and storage functions. Heatingthe whole tank of water all at once will take all day toproduce useful temperatures. Once hot, you had betteruse that hot water at the end of the day before thepoorly insulated tank loses its precious heat to the coldnight sky.

Most solar hot water system designs separate thecollector from the storage tank. This can optimize bothfunctions. Why not bring the tank in from the cold,insulate it well, and leave the collectors out in the sunwhere they belong?

What are the other advantages of separating thecollector from the storage tank? Increase the surfacearea of a collector, compared to the amount of waterbeing heated, and its temperature will rise more quickly.Configure the storage tank to keep the hottest waterapart from the coldest water in the tank and you’ll havehotter water available sooner. (See sidebar MaintainTemperature Stratification In Your Tank.)

There are also advantages in freezing climates. Byseparating the collector from the tank, you can put yourtank and piping indoors out of a freezing environment,and insulate them better for greater efficiency.

Flat Plate CollectorsFlat plate collectors are the most common solar thermalcollectors. They are most appropriate for lowtemperature applications (under 140°F; 60°C), such asdomestic hot water and space heating.

Closed

Open Open

From solarcollector

To housefaucets

To hotwater tank

From hotwater tank

Closed

Open

From solarcollector

To housefaucets

To hotwater tank

From hotwater tank

Closed

Using Hot Water Tank Bypassing Hot Water Tank

Solar Bypass Valve Configurations

Two roof-mounted flat plate collectors.


Solar Hot Water

A flat plate solar thermal collector usually consists ofcopper tubes fitted to a flat absorber plate. The mostcommon configuration is a series of parallel tubesconnected at each end by two pipes, the inlet and outletmanifolds. The flat plate assembly is contained withinan insulated box, and covered with low-iron, temperedglass. (See the diagram on page 45.)

The most efficient collector design maximizes solar heatgain, minimizes heat losses, and provides for the mostefficient heat transfer from absorber plate to tube.Operating temperatures up to 250°F (121°C) areobtainable, although neither common nor desirable.Remember, you want hot water, not steam.

Selective SurfaceA selective surface, often referred to as “black chrome”is far more efficient than a black painted absorbersurface. Although a black surface is most efficient atabsorbing solar radiation and converting it to heat, it isalso highly efficient at re-radiating long wave infraredheat back out. These losses reduce collector efficiency.

A highly polished chrome surface would re-radiate theleast infrared heat energy, but of course not beingblack, it would absorb very little. A selective surfacecombines the best of both worlds; high absorptancewith low emittance. Sound high-tech? It’s been aroundsince the 1950s, and is used on most commerciallyavailable flat plate collectors. Its performance is worththe marginal additional cost, particularly in cold climateswhere radiant heat loss is greatest.

Evacuated Tube CollectorsIf you want the highest efficiency solar thermal collector,you’ll be interested in an evacuated tube collector, suchas the one manufactured by Thermomax. Althoughevacuated tube collectors are more efficient thanconventional flat plate collectors, they costapproximately twice as much per square foot.

Each tube and fin of the collector is contained within aglass tube from which all the air has been evacuated.Why? Air carries heat from the hot surface of the tube tothe cooler surface of the glass to accelerate heat loss

by convection. Eliminate the air and you haveeliminated convective heat loss.

To minimize radiant heat loss, the tube is covered with aselective surface. Evacuated tube collectors are mostappropriate for high temperature applications (over140°F; 60°C). They are useful for more common lowtemperature applications too, such as domestic waterand space heating.

Collector to Tank InterfaceWith the collector and the storage tank separated, thesystem design must provide a flow of water (orantifreeze) from tank to collector and return. Smallcirculating pumps provide the necessary flow with verymodest energy requirements. Small hot water systemsmay use a direct current (DC) circulating pumppowered by a single PV module (10 to 30 wattsdepending upon power requirements). You may be ableto do without the pump altogether if you design fornatural thermosiphon flow.

Hot water returning from the collector should enterthe storage tank about a third of the way down fromthe top. This water may not be the hottest water youhave collected all day, because solar insolation andoutside ambient temperatures vary during the day.You don’t want this water to disturb the water at thevery top of the storage tank. Draw water for use fromthe very top of the tank. That is where it’s the hottest.

When hot water is drawn from the tank, it is replacedby new cold water, which should enter at the verybottom. Water circulating to the solar collector shouldbe drawn from the bottom of the tank. Why?Efficiency! Always supply your collector with thecoolest water you have available. The cooler a solarcollector runs, the less heat it loses to thesurrounding environment.

Maintain Temperature Stratification in Your Tank

A Thermomax evacuated tube collector.


Solar Hot Water

Drain Valve:Closed

Storage Tank:Backup heater

Hot In

HotOut

Flat PlateSolar

Collector

Cold toHouse

ColdSupply

PumpTempering Valve:Limits hot to house

Hot toHouse

Temp.Sensor

Temp.Sensor

Differential Control:Triggers pump based ontemperature differential

Valve:Main shutoff

PressureReliefValve

T & PReliefValve

Rust Never Sleeps:Open Loop

vs.Closed Loop

A “hydronic” system is one that uses a liquid asits heat transfer medium. The most commonalternatives to hydronic systems are air systems.Hydronic systems are nearly always categorizedas “open loop” or “closed loop”—often referredto as “direct” or “indirect” respectively. If you arenot aware of the difference between these, yourun the risk of discovering one day that yoursystem has been eaten alive by a slow yetpersistent killer—oxygen.

Open LoopOpen loop systems are subject to a periodicfresh supply of oxygen, ready to trash every bitof cast iron, steel, or other corrodible part in yoursystem. Whenever you draw water at the tap orbath, new water simultaneously moves in toreplace it. Along with that new water comes afresh supply of oxygen.

You have two lines of defense against damageby corrosive oxygen. You can prevent oxygenfrom entering the system, or you can usematerials that are resistant to corrosion. Copper,bronze, brass, stainless steel, plastic, and theglass lining of a hot water tank have no problemwith oxygen. Use these materials when dealingwith fresh water supplies associated with “open”or “direct” systems.

Closed LoopIf your system is a “closed system,” you won’thave to worry about oxygen. You will be able touse cast iron components (pumps), which cansave you money. Closed systems are chargedwith fluid at the time of installation. As apermanent part of the installed system, newoxygen is not introduced, and corrosion is not aproblem. Read on and you will see severalexamples of open and closed systems.

Another important consideration with open ordirect systems is whether or not you have hardwater. Over time, calcium deposits from hardwater will clog the collectors, ruining them.These deposits can be removed with periodicuse of a descaling solution. But if you have hardwater, you’ll be better off with a closed loopsystem.

Direct Pump Recirculation System

Thermosiphon System:Natural Flow Powered by GravityGravity powers convective flow in a thermosiphonsystem. Water in the collector becomes buoyant as it isheated, and it rises to an elevated tank. Cooler, heavierwater falls from the tank to take its place. For bestresults, place the top of the collectors at least one foot(30 cm) below the bottom of the tank. Greater heightdifferential will result in greater flow. Larger pipe, shorterruns, and gentle bends will make for an adequate flowrate.

If you require freeze protection, it’s not hard to do. Thecollectors can be filled with an antifreeze solution(propylene glycol is the most common). The heat canbe transferred to the domestic water via a heatexchanger.

Direct Pump RecirculationThe direct pump system uses an electric circulatingpump to move heat from the collector to the storagetank. This means that you are free from the constraintof placing the collector below the tank, as required forthermosiphon flow. The pump can move heat from thecollectors on the roof to a storage tank in the basement.Good sense still calls for minimal length of pipe run forefficiency.


Solar Hot Water

A differential controller turns the circulating pump on oroff as required. There are two sensors, one at the outletof the collectors, and the other at the bottom of the tank.They signal the controller to turn the pump on when thecollector outlet is 20°F (11°C) warmer than the bottomof the tank. It shuts off when the temperature differentialis reduced to 5°F (2.8°C). Some systems let you adjustthis hysteresis.

In climates where freezing occurs infrequently, arecirculation-type differential control will turn thecirculating pump on when the collector inlet temperaturefalls to 40°F (4.4°C). The philosophy behind this designis that the cost of heating your collectors with hot waterfrom your tank is low cost freeze protection if onlyrequired occasionally.

These systems were commonly used in the sunbelt,and only where freezing is a rare occasion.Recirculation systems are no longer very commonlyused due to vulnerability to freezing as a result of poweroutages, malfunction of sensor or controller, ordamaged sensor wires.

Draindown System (Not Recommended)A draindown system is an open loop system in whichthe collectors are filled with domestic water underhouse pressure when there is no danger of freezing.Once the system is filled, a differential controlleroperates a pump to move water from the tank throughthe collectors.

A draindown valve, invented in the 1970s exclusively forthese systems, provides the freeze protection function.When the collector inlet temperature falls to 40°F(4.4°C), the draindown valve, activated by the controller,isolates the collector inlet and outlet from the tank. Itsimultaneously opens a valve that allows water in thecollector to drain away. A vacuum breaker is alwaysinstalled at the top of the collectors to allow air to enterthe collectors at the top so water can drain out thebottom. Right next to the vacuum breaker, you’ll find anautomatic air vent to allow air to escape when thesystem fills again.

Draindown systems have proven to be the mostproblematic of all freeze protection systems. They arevulnerable to frozen vacuum breakers and air vents,damaged sensors or wiring, lack of proper pipedrainage, and malfunctions with the draindown valve.This type of system is rarely installed new any more,and is not recommended. Many were converted todrainback or closed-loop antifreeze systems.

Closed Loop Antifreeze Heat ExchangerClosed loop antifreeze systems provide the mostreliable protection from freezing. These systems

circulate an antifreeze solution through the collectorsand a heat exchanger. Propylene glycol is the mostcommon antifreeze solution. Unlike ethylene glycol(used in automobile radiators), propylene glycol is nottoxic.

The closed loop antifreeze systems generally have themost parts. You’ll find an expansion tank to allow theantifreeze to expand and contract with temperaturechange. You’ll find a pressure relief valve to protectagainst excessive pressures in the closed loop; aspring-loaded check valve to prevent reverse flow of theclosed loop at night so the collectors won’t dissipate theheat from the water heater; an air vent and/or aireliminator to help get the air out of the closed loop (airis your enemy—it can block fluid flow through thesystem); and a pressure gauge so you can tell if yoursystem is still charged. A couple of temperature gaugesare a good idea in any system so you can tell how wellyour system is operating.

There’s also one more assembly of fittings. Two boilerdrains with a shutoff valve in between will allow you tocharge the system with your charging pump. Onceready to charge the closed loop with your antifreeze

Pump

Drain Valve:Closed


Hot In

HotOut

Flat PlateSolar

Collector

Cold toHouse

ColdSupply

Tempering Valve:Limits hot to house

Hot toHouse

HeatExchanger:Antifreeze

T & PReliefValve

Hot In

HotOut

Auxiliary Tank

ExpansionTank

Pump

CheckValve

FromCold

Supply

PressureReliefValve

FillValve

DrainValve

Temp.Sensor

Differential Control:Triggers pump based ontemperature differential

Closed Loop Antifreeze Heat Exchanger System


Solar Hot Water

solution, a charging pump is used to circulate the fluidthroughout the loop, expelling all the air in the process.

Closed loop systems like this are quite common,whether they be for solar domestic hot water, radiantfloor heating, or hydronic baseboard heating. Despitethe many additional parts and fittings, they have a highdegree of reliability, and are well understood by heatingcontractors.

There is a downside to the closed loop antifreezesystem design. Once a solar water heating system hassatisfied its daily responsibilities, the system stopscirculating. Without circulation to remove heat from thecollectors, temperatures can climb to as high as 400°F(204°C).

These high stagnation temperatures, as they are called,can cause problems with air pockets and breakdown ofglycol antifreeze solutions. Air pockets form becausehigh temperatures drive dissolved gases out of solution.Systems using propylene glycol as the antifreeze mayuse an inhibitor additive to prolong the life of the glycol.Otherwise, the glycol can break down, resulting in asludgy deposit. Silicon and hydrocarbon oils have beenused to avoid these problems, but they are expensiveand are incompatible with seals and gaskets found inmost off-the-shelf components.

Drainback: A Simpler Closed LoopAlthough similar in name to the draindown type system,the drainback system is far different and much morereliable. It also provides some advantages over theclosed loop antifreeze system. Drainback systems mayuse water as the heat transfer fluid, since the collectorsdrain when not in operation. Antifreeze provides anextra measure of freeze protection from poor drainageand controller or sensor malfunctions.

A circulating pump operated by a differential control isturned on when the collector outlet is at least 20°F(11°C) warmer than the tank outlet. Water or anantifreeze solution is lifted from a small reservoir tankand circulated through the collectors and back to thetank. Heat is transferred to the domestic water via aheat exchanger in the reservoir tank. The circulationloop through the collectors is a closed loop. The wateror antifreeze solution is installed at the time ofinstallation, and does not present a recurring supply ofoxygen.

A drainback system requires a larger pump than any ofthe other systems described here. It must havesufficient capacity to lift the fluid to the highest point inthe system. When there is no more heat to be collected,the controller turns the pump off, and all the fluid drainsback to the reservoir tank. The collectors are empty.They can’t freeze, and they can’t overheat the

antifreeze. As a DIY homeowner, you won’t need aspecial charging pump either. When it comes time tochange the antifreeze, you can just drain and refill thereservoir tank.

The Choice is YoursThe system you choose will be determined first bywhether you need freeze protection. If you live in afreeze-free climate, choose a batch heater or smallthermosiphon unit for small systems serving one tothree people. Larger needs can be met with an openloop direct pump system circulating water from storagetank to flat plat collector.

If you need freeze protection or have hard water,choose one of the closed loop systems with antifreezeand a heat exchanger. Either one will heat your waterwithout fear of freezing.

Solar hot water is a good investment. Whether you area do-it-yourselfer with plumbing skills or want hire aprofessional installer, I suggest you locate a dealer whoserves your area. Ask their professional advice. Findout the products and services they have to offer, andwhich is the best fit for your needs and climate. Contactthe American Solar Energy Society or the Solar EnergyIndustries Association for assistance in locating acontractor or supplier in your area.

Pump Drain Valve:Closed


Hot In

HotOut

Flat PlateSolar

Collector

Cold toHouse

ColdSupply

Pump

Tempering Valve:Limits hot to house

Hot toHouse

Temp.Sensor

Temp.Sensor

Differential Control:Triggers pumps based ontemperature differential

DrainbackTank: Heatexchanger

inantifreeze

T & PReliefValve

Collectors and pipes should be slightly slantedto allow the water to drain from the collectors.

Closed Loop Drainback System


Solar Hot Water

AccessKen Olson, SoL Energy, PO Box 217, Carbondale, CO81623 • Fax: 559-751-2001 • [email protected]

AAA Solar Supply Inc., 2021 Zearing NW, Albuquerque,NM 87104 • 800-245-0311 or 505 243-4900Fax: 505-243-0885 • [email protected] • For more design and schematicdetail click on “Design Guide” then “Hot Water.”

Thermo Technologies, 5560 Sterrett Pl., Suite 115,Columbia, MD 21044 • 800-7SOLAR7 or 410-997-0778 Fax: 410-997-0779 • [email protected]

www.thermotechs.com • Thermomax evacuated tubecollector

American Solar Energy Society, 2400 Central Ave. G-1,Boulder, CO 80301• 303-443-3130 • Fax: 303-443-3212 [email protected] • www.ases.org

Solar Energy Industries Association, 1616 H St. NW,8th Floor, Washington, DC 20006 • 202-628-7745Fax: 202-628-7779 • [email protected] • www.seia.org

Tom Lane, Energy Conservation Services of NorthFlorida Inc., 6120 SW 13th St., Gainesville, FL 32608352-377-8866 • [email protected]

Solar Hot Water System Types: Advantages & Disadvantages

System Type Characteristic & Use Advantages Disadvantages

Solar Batch Water Heater Open loop; Integratedcollector & storage;

Freeze protection generallylimited to infrequent

or light freeze climates

Simple; No moving parts Freeze protectiontypically poor;

Inefficient in cold climates;Small systems only

Thermosiphon Typically open loop;May be closed loop with heat

exchanger & antifreeze

Simple; Requires noelectricity for operation

Collector must belocated below tank;

Inappropriate for use withhard water (open loop system)

Direct Pump System Open loop;Freeze-free climates

Flexible placement of tank& collector; can be

powered by PV

No freeze protection;Inappropriate for use with

hard water

Direct Pump RecirculationSystem

Open loop; Climates wherefreezing is an unexpected

occasion

Simple;can be powered by PV

Freeze protection is limitedto infrequent & light freezes;

Inappropriate for use withhard water

Draindown Open loop; Designed to drainwater when near freezing

Freeze protection isvulnerable to numerous

problems; Collectors & pipingmust have adequate slopeto drain; Inappropriate for

use with hard water

Can be powered by PV

Closed Loop Heat Exchanger Closed loop; Cold climates Very good freeze protection;Basic principles well

understood by conventionalplumbing trades;

No problems with hard water;can be powered by PV

Most complex of all systems,with many parts;

Heat exchanger & antifreezereduce efficiency; Fluid may

break down at highstagnation temperatures

Drainback Closed loop; Cold climates Very good freeze protectionif used with antifreeze;

No problems with hard water;Simplest of reliable freeze

protection systems;Fluid not subject to

stagnation temperatures;Simple to homebrew;

can be powered by PV

Heat exchanger & antifreezereduce efficiency;

Collectors & piping must haveadequate slope to drain;

Requires larger pump to lift


Backwoods Solar Electric SystemsFor an earth restored and a world at peace. Solar, Wind, Hydro

Independent Electric Power for the Remote Home where utility power is not available.

When you speak with Backwoods Solar, your questions arepersonally answered by people using the products everyday.Our catalog / planning guide teaches the basics of installingsolar electric residential power. We can refer you to skilledinstallers in most states. Our mountaintop business, shop, andhome have been powered by equipment from our catalog for25 years. Utility lines are still 2 miles away. We are a familybusiness living with our products.

177 PAGE CATALOG / PLANNING GUIDEFREE to Home Power readers

Phone (208) 263-4290 FAX only (888) 263-4290Website www.backwoodssolar.comEmail [email protected]

Visit us or write:Backwoods Solar Electric Systems1395-HP Rolling Thunder RidgeSandpoint, Idaho 83864 USA


SERVING THE SOUTHERN UNITED STATES & CARIBBEAN

FULL SERVICE CONTRACTING & SUBCONTRACTING

FROM CONCEPTION TO COMPLETION.WE’LL ALSO INSTALL YOUR EQUIPMENT AT YOUR SITE.

6120 SW 13th Street • Gainesville, Florida 32608 • USA • www.ecs-solar.com • [email protected]

Tropical Solar ContractorsSOLAR ELECTRIC, HOT WATER & POOL HEATING

(352) 377-8866

MEMBER

SOLAR CONTRACTING SINCE 1977LIC #CVC056643

Jamie on a job in the Bahamas.


See Ya at the TexasRenewable Energy Roundup

Sept 28–30 Fredericksburg

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n September of 1998, I received aletter from a Canadian missionary,Grace Birnie, who is doing language

translation for the Feri people ofnortheastern Benin. Her translationwork required her to move to a smallvillage in a rural part of Benin that wasnot served by utility power. Grace waslooking for information about solar-electric systems, and I was happy toprovide it.My wife and I had worked in Niger during the ‘60s. Inthe intervening years, I made a number of trips to installsolar-electric systems for small Bible schools scatteredthroughout the “boonies” of Niger, Burkina Faso, andBenin.

Benin, just west of Nigeria, measures about 675 miles(1,090 km) from north to south and about 325 miles(520 km) from east to west, and is shaped much like alarge turkey drumstick. Most of its 4.5 million people livenear the coast. Some of the larger cities have electricity.But only 6 million kilowatt-hours (KWH) of the 251

million KWH used each year is produced in the country,and it comes from diesel generators. The rest comesfrom hydroelectric dams in nearby Ghana.

Grace had been working in the town of Kandi, one of thelarger towns of Benin. In order to be nearer to thelanguage group she works with, her organization decidedto move her to a small village called Pede, several milesnorth of Kandi. Living in the village was more practical forher language work, but it meant that she would bewithout the five amps (at 220 VAC, 50 Hz) of electricservice she had from Kandi’s small diesel generators.

In Pede, she would need power to operate hercomputer and printer, as well as lights, a well pump,and other household appliances to survive in the sub-Sahara climate. Daytime temperatures soar to 115°F(46°C) or higher in the October to April dry season.

Grace heard that I had been bringing out work teamsfrom the United States to set up small, 12 voltphotovoltaic systems for several schools in northernBenin. She asked if I could help her get power for hernew house. Grace asked for a solar-powered systemthat would deliver 220 VAC, 50 Hz power to operate herhousehold appliances. In May 1999, the project beganin earnest. We had to make decisions about sizing,funding, and the logistics of getting equipment throughcustoms and into the country.

Wightman Weese©2001 Wightman Weese

The crew installing the fourth array.The photovoltaics were set at 15° south.

System SizingFirst we had to determine how much energy sheneeded for the small house that was being built for her.We developed a usage chart and began negotiatingmaximum and minimum uses. We needed todetermine:

• The amount of usage each day, to determine thebattery bank size and the number of solar modulesneeded.

• The maximum amperage at any given time of day, toensure that the inverter we chose could produceenough power to keep refrigerator and well-pumpmotors from stalling due to insufficient inverter outputcurrent.

All the numbers, Grace told us, were maximums. Shethought she would rarely exceed these, and would mostoften use considerably less. For instance, the guestroom could go for weeks without being occupied. Herwater usage, she said, was less than 100 gallons (380 l) a day, which the pump could supply in a matterof minutes.

ModulesTo begin the design, we needed to know how manyhours of effective sunlight would be available to us atthat location, which was 11° North latitude and 3° Eastlongitude. We referred to a valuable study recorded onthe Web by NASA (http://eosweb.larc.nasa.gov/sse).

The NASA study shows the “surface solar energy dataset,” which divides up the globe into rectangular cells.The program can show insolation data for any part ofthe world. The table (see next page) shows the data forGrace’s location, cell #3873. This area of northeastBenin gets an average of six to seven hours per day ofeffective sunlight. We made our calculations based onsix and a half hours per day.

We calculated as follows, based on3,800 watt-hours per day: 3,590 x 1.1to compensate for system losses = 3,949 watt-hours per day. For a 12volt system, this comes to 329 amp-hours per day. We selected 65watt Solarex modules, which wererated to produce roughly 4 amps.

Using the calculation of 330 AH perday, we divided 330 by 6.5 sunhours per day to arrive at 50.7,which is the amperage requiredfrom the solar array. With themodules we’d chosen, this meantwe actual ly needed at least 13modules (50.7 ÷ 4 = 12.6).


International

Unfortunately, we had brought only twelve moduleswith us, not realizing that the 1/2 HP water pump(Meyers submersible #7GSO5R/SO4942) drew somuch. To be safe, we perhaps should have installedfourteen or sixteen modules. We had to hope thatGrace would be very frugal and keep her energy usageto a minimum. (When we returned to upgrade thesystem, we added four more modules, bringing thetotal to sixteen.)

Map: Benin, ca. 1992. Courtesy of The General Libraries, The University of Texas at Austin. Benin’s national flag has been added by HP.

Grace Birnie’s house was built with hand tools and sun-dried bricks.


International

InverterWe were designing a 220 volt system, calculating thatwe would need at least 320 AH per day. We probablyshould have opted for a 3.3 KW inverter, but we sawfrom the usage table that rarely would more than 2,000watts at 220 volts be drawn at any one time. Trying tosave some money, we decided on a 2.6 KW Trace

inverter (SW2612E), which is rated at 28 ampsmaximum at 220 VAC. This inverter has a peakconversion efficiency of 90 percent.

BatteriesOne major problem of overseas installations of solar-electric systems is the battery issue. Gel-type batteriesdo not operate well in hot weather. And lead-acidbatteries have to be shipped by surface carrier.Customs charges for most African countries also makethe price prohibitive. Some people have used regulartruck batteries, but the thin plates don’t last very long insolar-electric systems.

Local prices were high—more than US$200 apiece. Butimporting solar batteries from the States or Europe,including overland shipping, would be very expensive.We decided we were better off buying locally.

After a long search, we found an African dealer whosold so-called “solar batteries.” The label stating thatthey were made in Germany was a photocopied sheet,lightly pasted on the batteries, which bore no othertrademark.

They were 12 volt batteries rated at 105 AH, with anunusual cell arrangement. Rather than six cells in arow, there were two rows of three cells. The terminals

Benin Monthly Insolation

Month Average Minimum MaximumJanuary 6.22 5.94 6.42February 6.75 6.50 6.92March 6.53 6.00 6.78April 6.66 6.51 6.80May 6.84 6.24 7.28June 6.30 6.23 6.46July 5.53 4.93 5.94August 5.31 4.84 5.55September 5.67 5.44 5.96October 6.54 6.37 6.75November 6.42 6.23 6.58December 5.78 5.63 5.98

2 per day)(KWH per m

Courtesy NASA, http://eosweb.larc.nasa.gov/sse

Birnie LoadsHours of Typical Power Usage

6-8 8 AM- 12-2 2-6 6-8 8-11 11 PM-Item Watts Hrs/day Avg WH/day AM Noon PM PM PM PM 6:00 AM

Outside security lights 40 10.0 400 40 40 40Kitchen lights 40 3.0 240 80 80 80

400 0.5 200 400 400 400 400 400 400 400Master bedroom lights 40 2.0 160 40 40 80 80Livingroom lights 40 3.0 120 80 80Dining area lights 40 3.0 120 40 80Guest room lights 40 1.0 40 40 40Bath lights 20 2.0 40 40 40 40 40Hallway lights 20 1.0 20 20 20Porch lights 20 1.0 20 20 20Storage lights 20 0.5 10 20 20 20

AppliancesRefrigerator 145 8.0 1,160 145 145 145 145 145 145 145Computer 300 3.0 900 300 300 300 300 300 300Blow dryer 1,000 0.1 70 1000Microwave 500 0.1 35 500 500Hand mixer 200 0.2 30 200Printer 30 0.5 25 50 50 50 50 50

Totals 3,590 2,065 895 1,575 1,095 1,895 1,215 585

Pump, 1/2 hp


International

were mounted very close togetheron the same end of the battery,making them very tedious to hook upwithout short circuiting.

Cloudy periods can last for two orthree days, and there are seasonalHarmattan winds, bearing dustclouds that slightly obscure the sun.We wanted to have enough batterycapacity to give some leeway. To beon the safe side, we purchasedtwelve of the batteries from a dealerin Cotonou.

We wired the batteries in parallel,which theoretically gave us 1,260 AHat 12 VDC. We had to consider anallowable level of battery discharge toinsure reasonable battery life. Weweren’t sure how carefully the systemwould be monitored, or whether thebatteries would be discharged toodeeply. So we allowed for a 25percent discharge limit. Drawing anaverage of 320 AH per day, thebatteries would not be dischargedbelow 75 percent state of charge,except on very cloudy days.

Temperatures affect batteryeffectiveness. 78°F (26°C) is the idealtemperature for optimum batteryperformance. Since ambienttemperatures in that region averagefrom 75 to 110°F (24–43°C), we didn’tthink the batteries, stored on a shadyporch area, would be greatly affected.

It didn’t take us long to realize thatpurchasing the local batteries was amistake. They began to fail veryquickly, resulting in another quick tripto Benin from the U.S. with eight 350amp-hour Trojan batteries. Thatgave us 1,400 amp-hours of batterypower to replace the 1,260 amp-hour bank that failed.

Other EquipmentThe 12 PV modules were parallelwired into four subarrays of fourmodules each. The modules weremounted on the roof, and eight #6(13 mm2) stranded copperconductors (a major positive and amajor negative for each four modulesubarray) were run to a combinerbox located in the kitchen. The #6

Power Conversion Center

Charge Controller: Trace TC60,60 amp, with 60 amp breaker

Combiner BoxMeter:

Trace TM500(shown with Trace’s

circuit board)

DC Disconnect:Trace DC 250

Inverter:Trace SW2612E,

2.6 KW 220 VAC 50 Hz

To 220 VACbreaker box and

house loads

Batteries: Eight Trojan L16G, 6 V lead-acid cells,1,400 amp-hours at 12 VDC Fuse:

TraceTFB300

Photovoltaics:Subarrays #1, #2, & #3 (top):

Twelve Solarex SX-65U,65 W modules. Subarray #4(bottom): four Siemens M55,55 W modules. Array total:

1,000 watts at 12 VDC.

14.5

Grounds NotShown

copper wire gave us an acceptablevoltage drop of under 2 percent.

From the combiner box, we ran thePV output to a Trace TC60 charge

The lead-acid batteries live outsidein West Africa’s temperate climate.


International

controller, which is rated to handle 60 continuous amps.The TC60 has a built-in 60 amp, DC rated breaker thatprovides overcurrent protection for the PV array output.

The charge controller has a battery level indicator, butto be safe, we decided to also use a Trace TM500 amp-hour meter. This meter operates much like a fuel gaugekeeping track of state of battery charge, as well asother useful information. The user can tell at a glancewhether the system is in good working order and notovercharging or undercharging the batteries.

We needed a DC disconnect and a substantial fusebetween the batteries and the Trace inverter(SW2612E). We installed a Trace TFB300 fuse blockand a Trace DC250 DC disconnect.

InstallationWe installed the batteries, controller, meters,disconnects, and inverter on the same wall. Thebatteries are outside on the screened-in patio, on theother side of the wall. Four of our team members andsome casual laborers did the installation. From start tofinish, it took us from Wednesday afternoon to Saturdayafternoon—a total of about 24 working hours for thecrew.

We had one disappointment. The local electrician,who was to install all the lighting fixtures and otherappliances, hadn’t finished his work by the time wehad to leave. So we weren’t able to see the house litup and appliances running. We did see 220 volts ACon the voltmeter, which is what we came to Africa todeliver.

Solar AlternativeWhat was the alternative to a solar-electric system?Perhaps Grace could have used a generator, whichwould cost more than US$5,000 in Benin. Fuel cost in

that part of the country ranges from US$3-5 per gallon.It would not have taken long to eat up the US$9,000that Grace spent on this system. And with Harmattandust storms, which play havoc with machinery, agenerator might need to be replaced within eight to tenyears. We believe that this solar-electric installation waswell designed, and should deliver adequate power foryears to come.

AccessWightman Weese, 1114 E. Wakeman Ave., Wheaton, IL60187 • 630-665-9064 • [email protected]

Grace Birnie, SIM, B.P. 16, Kandi, Republic of [email protected]

Atlantic Solar Products, 9351 J Philadelphia Rd.,Baltimore, MD 21237 • 800-807-2857 or 410-686-2500Fax: 410-686-6221 • [email protected] • System equipment

Birnie System Costs

Item Cost (US$)12 Solarex modules SX-65U 3,492.00

Trace SW2612E inverter, 2.6 KVA 2,026.504 Siemens modules SM55 1,560.008 Trojan L16G 6 volt batteries 600.00TC60 charge controller, 60 amp 230.30Trace DC250 disconnect 217.00Well pump 185.21

171.50Pump motor 149.00Cable, battery interconnects, etc. 120.00

52.50Spare fuse 26.60

Total $8,830.61

Trace TM500 power meter

Trace TFB300 inverter fuse and holder

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an logging be an ecologicalactivity? Can we use modern fellingand milling equipment without

noise, fumes, or fossil fuels? Can solarlogging be part of a viable way of life?Rico, Mary, and Brad say, “Yes!”Rico and Mary Meleski are homesteaders. They havespent twenty-five years learning the skills of backwoodsliving. They live at an elevation of 9,400 feet (2,865 m)in the southern Rocky Mountains, 10 miles (16 km)from a paved road and about that far from the nearestpower line.

They are part of a loose-knit community of back-to-the-landers that has inhabited northern New Mexico sincethe late 1960s. Photovoltaic (solar-electric) powersystems have been common there since the early1980s, largely due to the efforts of Brad Rose, the local“solar gizmologist.”

In August 1996, Rico and Mary took a job as caretakersof a piece of private land surrounded by national forest.They formed Edge Habitat Associates, a non-profitorganization, to offer wilderness experience throughguided excursions, and to demonstrate traditional

homestead living. They believe it’s easier to spend less,without all the trappings of modern America, than tostruggle to earn more.

Rico and Mary’s 12-year-old daughter Aspen thrives onthe adventures of backwoods living, learning about lifedirectly, as well reading and studying. During theisolation of winter, Brad sometimes skis in with hisdaughter Sophia, who is Aspen’s best friend. Duringwarmer weather, Sophia occasionally comes up withher school class on a field trip.

Rico and Mary built their cabin from logs and rock,insulated it with straw, and plastered it with clay. Duringthe winter, their only way in and out is on skis. They buybulk food from a cooperative twice a year, grow aprolific garden, and store food in a root cellar. Theymake their own beeswax candles, and wash theirclothes in a bucket with a plunger. For supplementaryincome, they make toys and art items from wood andhand-felted wool, to sell locally and through catalogs.Their skills have been honed by decades of experience.

Only a few chores are delegated to twentieth centurygadgets. A solar water pump draws from a shallow wellto fill storage tanks for the animals and for the kitchen(where a hand pump fi l ls the sink). A 75 wattphotovoltaic (PV) module at the toolshed powers their

Windy Dankoff ©2001 Windy Dankoff

Ingot the horse pulls Rico and the solar power trailer that runs the chain saws.

Solar Powered Logging and Lumber MillingSolar Powered Logging and Lumber Milling


Photovoltaics

grain mill and blender. A tiny 10 wattPV module powers a radio/cassetteplayer, which is the only electricaldevice in their cabin. Mary keepstheir few plastic kitchen items hiddenfrom sight to maintain a rusticatmosphere.

Trouble in ParadiseOne windy night in April of 1997,tornado warnings were posted forthe plains on the other (east) side ofthe mountains. Mary and Rico wereawakened by a violent blast of wind.The cabin trembled. It sounded likea jumbo jet was landing on the roof.When they looked outside in themorning, the scene resembled a warzone. Eighty foot (25 m) tall treesthat had once dominated the landscape were moweddown like weeds. A nearby hillside was dotted with rootballs torn from the frozen earth.

Rico and Mary were unhurt, but they had a mess ontheir hands, and a potential fire hazard. They also sawthat they had a windfall of potential firewood and sprucelumber that could be sold to local builders.

They considered contracting with alocal logging company to clear thefallen trees and to mill the lumber,but they had seen too muchdestruction left by heavy loggingtrucks and equipment. They figuredthey could do the clearingthemselves, with much less impacton the land. That summer, they wentto work clearing the land usingconventional gasoline-poweredchain saws and a pickup truck.

Horse LoggingTheir first difficulty was dragginglogs by truck from a tangled mass oftrees, on muddy or snowy ground.They needed a more agiletechnique. Horse-drawn logging is anorthern New Mexico tradition thatgoes way back. And what could bemore solar-powered than a horsewho eats grass?

Rico and Mary bought a pair ofNorwegian Fjord workhorses from abreeder who was thrilled to see themmove to the high country and “get alife.” The breed dates back to the

Viking era when they were used to pull logs and ships.Rico took a crash course in harnessing real horsepowerfrom some western movie stunt men who wereacquaintances of the breeders, and went right to work.

These horses are built for power, not for speed. With atraditional harness they can pull an enormous load.Rico says he has more to learn than the horses, butwith gentle patience, they are developing a language of

Ingot pulls a log without spinning his wheels.

Brad Rose demonstrates the solar-powered sawmill.


Photovoltaics

nudges and commands. Rico studied old cargo sleds,and then built his own with old skis screwed to therunners. The sled has a hitch ball to pull a trailer—aninterface with this century.

The Lumber MillWood can be burned for heat, or it can supply perpetualheat through the construction of solar-heated homesand sun-space additions, which are common in thissunny mountain region. A sawmill makes the differenceby turning trees into lumber.

Rico and Mary bought a portable bandsaw mill that cutswith very little waste. Their Norwood Mark 4 mill wassupplied with a 9 HP Honda gasoline engine. It turnsout fine lumber, rough sawn but not ragged. They hadno trouble finding a market for the lumber by word ofmouth.

Petrol in ParadiseMary and Rico love the peace and quiet of thewilderness, so the first year of their salvage loggingoperation seemed like an eternity. Exhaust fumes fromthe saws and the mill stunk up the whole valley, and thenoise could be heard a mile away. Mary and Rico hadenjoyed a nearly petroleum-free lifestyle, and wanted tokeep it that way.

Dry weather caused another problem. Due to droughtconditions, the Forest Service prohibited the use ofgasoline equipment during much of the time when theywanted to work.

They were already using PVs to runtheir water pump, grain mill, blender,and radio with systems installed byBrad Rose. Brad had been runninghis home and workshop machineryon solar energy since the early1980s. Mary wondered if he couldn’trig a system to run the sawmillwithout all the noise and fumes.

Solar Electricity for the SawmillThe manufacturer of the mill offersan AC electric motor, but that wouldhave required two large inverterscosting close to US$6,000. From hisexperience with solar pumps andshop machinery, Brad knew that aDC motor would eliminate the needfor the inverters, and would use lessenergy because there would be noinverter losses.

This was a low-budget project thathad to pay for itself. Brad wonderedwhere to get a DC motor of sufficienthorsepower at a junkyard price. He

thought a used electric golf cart motor might do the job.He located a golf cart repair shop with lots of old parts,and an owner who didn’t think he was crazy. He boughta 36 volt motor from a Cushman cart that was verycommon in the 1960s and ‘70s. It used a belt drive,which made the motor adaptable to the sawmill.

Brad bolted the motor to the mill and wired it to six golfcart batteries. It worked perfectly! The golf cart motorhad all the power they needed for the soft spruce theyare cutting. Electric vehicle motors handle overloadsmore gracefully than gasoline or AC motors becausethey respond with an increase of torque instead ofpartially stalling.

The solar-electric sawmill turns a log into lumber.

This recycled golf cart motor turns the sawmill blade.


Photovoltaics

The mill is not only quiet, it eliminates the vibration andpulsations of the gasoline engine. The mill holds itsadjustments better, and the blade stays sharp at leasttwice as long. Blade sharpening is very timeconsuming, so this was a welcome benefit.

To power the mill, the loggers wired a 585 watt solararray, with sets of three panels wired in series for 36volts. They bolted this array to the roof of the mill shed.The array consists of three Photowatt 75 watt modulesand six Solarex MSX-60 modules. The modules weredonated.

The battery bank is six Trojan T-105 golf cart batteries.A B.Z. Products ICC16-36 (16 A, 36 V, temperature-compensated) charge controller prevents overcharge ofthe battery when there is excess energy. A fuseprevents hazardous overcurrent if the blade gets stuckor if there’s a short circuit. The system is really quitesimple.

Sawmill Conversion DetailsA golf cart motor works perfectly for the portablesawmill. They come in various sizes. Their nameplatesdon’t usually list horsepower, but they do show a ratingof current draw that ranges from about 60 to 110 amps.110 amps X 36 volts = 3,960 watts. At about 75 percentmotor efficiency, that’s 4 HP.

The mill manufacturer offers a 10 hp AC motor, butsoftwood like spruce doesn’t require that much. Thesolar loggers used a GE 36 volt, 110 amp golf cartmotor, reconditioned. It draws full current (and slowsdown a bit) only when making 16 to 20 inch (40–50 cm)cuts or hitting hard knots. If more power is required (forcutting hardwood, for example), a second, identicalmotor could be added using a double belt drive.Sometimes larger DC motors can be obtained fromsurplus catalogs. New 90 VDC motors are alsoavailable from industrial motor suppliers.

The old Cushman motor fit the mill with little more effortthan spinning four nuts onto four bolts. Golf cart motorshave a tapered shaft and require a pulley to match.Brad got 3 inch and 4 inch (7.6 and 10 cm) pulleys withthe motor. The 4 inch pulley would run the saw faster,and it worked fine without overloading the motor. Thegasoline engine had a centrifugal clutch, but that wasn’t

necessary with the electric motor. Speed control is notneeded either.

Welding cable was used to carry the power to the motoron the moving carriage. It is large enough to producealmost no voltage drop. For the on/off switch, they usedan inexpensive marine battery switch. It took less than aday to convert the mill to DC power. An emergency stopbutton will be the next addition.

36 volts is the standard for older golf carts, but it is not anormal standard for PV systems. The PV array andbattery bank are easily configured for it, since theycome in 12 and 6 volt increments, respectively. B.Z.Products makes 36 volt charge controllers. An

Brad displays a finished board from the solar-powered sawmill.

Sawmill System Costs

Item Cost (US$)Norwood Mark 4 sawmill without motor $4,5603 Solarex and 3 Photowatt PV modules 2,925PV mounting racks, adjustable tilt 3806 Trojan T-105 batteries 330Fused disconnect switch & misc. electrical 220Golf cart motor, reconditioned, 36 V, 4 HP 120BZ Products charge controller 8570 feet #4 welding cable 65

Total $8,685

Power Draw of the Mill: On a Typical Full Load Cut(10 inch (25 cm) wide spruce log)

Voltage at the motor, under load 34.0 voltsAverage current draw (80 to 130 amps) 105 ampsAverage power (105 A x 34 V) 3,570 wattsStarting surge 410 amps


Photovoltaics

important feature of the controller is temperaturecompensation, because batteries require a higherfinish-charging voltage during the cold winter months.

Solar Power for the Chain SawsThe sawmill worked so well that the solar loggersdecided to tackle the chain saws. Brad knew that thepower system could be built using the samecomponents used in remote solar-powered homes. Thedesign process would also be the same. He needed anestimate of the energy needs of the machines—thewatts that they draw multiplied by the daily hours of use.

The solar loggers purchased an electric chain saw, andtried it out using some old batteries and a borrowedinverter (to convert DC to standard AC). That gave themthe data they needed, plus the inspiration derived fromseeing it actually work.

Brad then designed a power system to run two saws forabout four cutting hours per day. The 340 wattphotovoltaic (PV) array is made up of four BP-585 85watt modules. Four Exide GC-4 golf cart batteries, a B.Z. Products ICC16-24 charge controller (16 A, 24 V,temperature-compensated), and a 3,600 watt invertercomplete the system. It’s all mounted on a little home-built trailer, made from an old pickup bed and chassis.

The loggers now use two electric chain saws. Thelarger saw is a Stihl E220 (115 VAC, 15 A), whichperforms as well as a good gasoline-powered saw.Their smaller Husqvarna Electric 16 (115 VAC, 13 A) isideal for trimming limbs and for smaller trunks.

These are 115 VAC power tools. No one makes lowvoltage DC chain saws because the power cable wouldbe too large, heavy, and expensive. These saws can beordered from your local chain saw shop.

Both saws can be used for half the day almost everyday. Sometimes Rico and Brad cut all day, drawing thebatteries down to a fairly low state of charge. If they dosomething else the next day, the batteries recover afterabout one day of sun.

Not Enough Macho?The benefit of electric saws goes far beyond theelimination of fuel and noise. There is no enginemaintenance. As with the sawmill, the chain saw teethstay sharp two or three times as long because thepower is applied without the pulsations of a pistonengine.

The saws are also much less stressful to use. Whenyou stop a cut with a gasoline tool, the engine keepsidling. It makes you want to hurry to the next cut. Theelectric saws stop completely between cuts. Theoperator tends to be more relaxed, and makes betterdecisions under potentially hazardous conditions.

Most important, Rico figures that he experiences halfthe physical stress. His hands have been injured byyears of gas-powered chain saw use. The vibrationcauses him pain, but he has no trouble using an electricsaw for hours at a time. Each saw has a 100 foot (30m) extension cord (#12 (3 mm2) construction grade) todrag around, but that takes less effort than refuelingand messing with engines. They keep one gasolinechain saw handy for occasional clearing beyond reachof the cords.A solar-electric chain saw quickly reduces

fallen aspen to firewood.

Power Draw of the Stihl E220 Saw: On a TypicalFull Load Cut (12 inch (30 cm) spruce log)

Voltage at the battery 24.0 VDC current draw, average 85 AAverage power: 85 amps x 24 V 2,040 wattsStarting surge 256 amps

Electric Chain Saw System Costs

Item Cost (US$)4 BP-585 PV modules, 340 W at 24 V $1,870Trace DR-3624 inverter, 3,600 W 1,600Stihl E220 chain saw 5254 Exide GC-4 golf cart batteries 220Fused disconnect switch & misc. electrical 240Husqvarna Electric 16 chain saw 220PV mounting rack 85BZ Products charge controller 75Trailer, salvaged pickup 0

Total $4,835


Photovoltaics

The quiet whir of the chain saws is amusing to visitors.One said “it sounds more like a sewing bee here.”Another, getting right to the point, grumbled “it just don’tgot enough macho.” Rico lets visitors make a few cuts,and then they see the light.

Is There Enough Energy?One full day of lumber milling draws the batteries downto a fairly low charge level. It takes about one day torecharge after that. The same is true for the chain sawoperation. So by rotating work between the two chores,the loggers can work all they want to. When it’s cloudyfor a few days, there is always hand and horse work todo, or they can take time off.

These two systems have minimal battery banks. If thebattery capacity were to be doubled, it would lengthenthe working (and recharging) periods. In a cloudyclimate, both the solar arrays and battery banks wouldneed to be larger.

Is Solar Logging Economical?This project was accomplished using standard, easilyavailable components. It can be reproduced. It isn’tcheap, but it can be economical under the rightconditions.

One example is Forest Service contracting, especiallyfor thinning in sensitive watersheds where petroleumpollution is unacceptable. It also makes sense where

Other Solar EnergySystems at Edge Habitat

The home cabin uses a 10 watt PV module tocharge two golf cart batteries. The only load is acar radio/cassette player. The PV module is thethin-film amorphous type that Brad obtained as asample, back when it was introduced to themarket. Thin-film modules are less affected bypartial shading than the crystalline modules usedin the logging systems. It was chosen becauseshadows of tree branches can’t be avoided atthe cabin.

The toolshed system uses one Photowatt 75watt PV module, an 8 amp charge controller, andfour golf cart batteries. The batteries are tenyears old and in poor condition, but they aregood enough for intermittent use of a flour mill, ablender, and the blade sharpener for the sawmill.A 300 watt inverter runs the blender andsharpener. The flour mill is belt-driven by a 12volt, 1/4 HP motor.

The water supply system was the first solarenergy system that Brad installed at the site. Ittook the place of an AC shallow well jet pumpand a generator in 1987. The pump is a SolarSlowpump by Dankoff Solar Products. It hangssuspended 5 feet (1.5 m) below grade, justabove the high water level. It pumps the wateruphill 45 vertical feet (14 m) to a 1,000 gallon(3,800 l) buried concrete tank at the cabin.

Water is delivered to the kitchen sink by an old-fashioned hand pitcher pump next to the sink.The Slowpump also pushes water up 60 verticalfeet (18 m) to another 1,000 gallon galvanizedtank, for seasonal use, to water the garden andanimals.

It was not feasible to bury all the water pipesdeep enough to protect them from freezing. Thewater is pumped about once per week. Whenthe pump is turned off, water drains back downfrom the pipes. When the pump is not running,solar electricity is stored in a battery bank. ThePV array is a single Arco M-53 module (43watts) charging two golf cart batteries.Rechargeable flashlight batteries are alsocharged by this system, using a 12 volt batterycharger.

This 10 watt thin-film PV module supplies the only electricity for the home cabin.


Photovoltaics

noise is a problem, in burn areas, and where fire hazardis frequently declared. The U.S. Forest Service andNational Park Service already use PV for waterpumping, campground lavatory lighting, lookout towers,and environmental monitoring. They recognize solarpower’s practicality.

Milling valuable hardwoods can be lucrative, and canpay for the mill and the power system in a reasonabletime. When boards come directly out of the woods,transport of material is greatly reduced and waste isreturned to the forest. The system also can be used toclear land for settlement, and to mill lumber to build ahouse. Next, the power system can run constructiontools to build the house, and finally, it can power thehome itself.

By switching to solar power, the solar loggers havegreatly reduced their maintenance time and expenses.Their electrical systems will last much longer thangasoline engines. In the long run, their investment willpay off, and they will probably stay healthier as well.These are the expected benefits. An unexpected benefithas already paid off, in the form of community relations.

Community FlourishesThe solar loggers spread the good word about solarpower by offering free firewood to the community, andselling custom-milled lumber. The results have beennothing short of social magic, introducing them to manyof the local old-timers, and breaking down culturalbarriers.

Some of the local people had grown up helping theirfathers and grandfathers to log with horses. There wasone older fellow who had never liked the “hippies.” Hecame to see the solar logging operation, and it finallywarmed him up. He has since returned many times,bringing gifts, and bringing his family up to get wood.He gave Rico a pile of horse equipment that had beenstored in his shed for decades.

Children get a special thrill out of seeing the wholeprocess, from the logs in the woods to the stacks oflumber that will soon be part of somebody’s home, alldone cleanly and quietly. For the solar loggers, this hasbeen the biggest return on their investment!

It Works!When a project like this works so well on so manydifferent levels, it becomes a source of enthusiasm andpride. The solar loggers want to share this experiencewith the world. They want you to know that you too canlog on, and on, and on, in a cleaner, safer, moresustainable way.

AccessWindy Dankoff, Dankoff Solar Products, Inc., 2810

Industrial Rd., Santa Fe, NM 87505 • [email protected] • www.dankoffsolar.com

Rico and Mary Meleski, Edge Habitat Mountain Center,HCR 65 Box 16, Ojo Sarco, NM 87521 • Edge HabitatAssociates is a non-profit organization. Donations aretax deductible, and visitors are always welcome.

Brad Rose, PO Box 1, Ojo Sarco, NM 87521505-689-2455

Norwegian Fjord Horse Registry, 1203 Appian Dr.,Webster, NY 14580 • 716-872-4114Fax: 716-787-0497 • [email protected] • Draft horse information

Norwood Industries Inc., 252 Sonwil Dr., Buffalo, NY14225 • 800-567-0404 or 705-689-2800Fax: 705-689-1982 • [email protected] www.norwoodindustries.com • Sawmill

B. Z. Products, 7614 Marion Ct., St. Louis, MO 63143314-644-2490 • Fax: 314-644-6121 • [email protected] Controller

Stihl Incorporated, 536 Viking Dr., Virginia Beach, VA23452 • 800-467-8445 or 757-486-9100Fax: 757-498-7560 • [email protected] • Chain saws

Husqvarna Forest & Garden Co., 7349 Statesville Rd.Charlotte NC 28269 • 800-438-7297 or 704-597-5000Fax: 704-597-8802 • www.husqvarna.com • Chain saws

Thanks to Frances Tyson who donated the PV arrayused for the sawmill.

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he motivation for this projectcame from reading the review ofthe LED torches in HP81. I’ve

been using LED bike lights for severalyears now, and have replaced the smallbulbs in penlight torches with red LEDsfor use in the photographic darkroom,where a localised bright safelight canbe most useful. But I had neverventured into the use of LEDs for a“proper torch.”In the United Kingdom, we seem to be years behind theUnited States with such innovations. When they dobecome available, we tend to pay dollar prices in UKpounds, so things cost around half again what they doin the States. Internet buying is of course an option, butfreight charges, import duties, and customs chargesalmost double the cost.

I set out to make a simple conversion for an existingtorch (“flashlight” to Americans) that would give me theefficiency and longevity of a similar commercial product.This proved to be quite simple to do, and may be ofinterest to others in a similar situation, or to anyone whoprefers to modify a commercial torch rather than buy amanufactured LED torch.

The Choice of TorchBecause this was going to be quite an expensiveexercise, it seemed foolish to skimp on the cost of thetorch body itself. I wanted to produce a torch that wouldlast for many years. The three main criteria for the torchwere robustness, water resistance, and ease ofconnection for the new light unit. The torch also had tobe of a three-cell design to give sufficient voltage for thewhite LEDs.

My choice was a three C-cell Mag-Lite, available fromany good hardware or camping store. Thoughexpensive on this side of the pond, it fulfilled all of therequirements. It is very robust, has a good positiveswitch, is fully waterproof, and has a very simple andelectr ical ly sound method of making al l theconnections.

LEDsLight emitting diodes (LEDs) have improved over thelast few years, with extremely high levels of outputpossible. There could be only one criterion for the LEDsfor this project—the highest output possible!

There’s not a lot of choice here in the UK, and again wetend to pay about half as much again as in the U.S. Thebrightest white LEDs that I could find were 5 mm, 20degree types rated at 3,000 millicandelas (mcd) whiledrawing a current of 20 mA. (I believe that these areequilvalent to those advertised as 5,600 mcd whiledrawing 30 mA.)

Peter Jones©2001 Peter Jones

Converting A Flashlightto LEDs

Converting A Flashlightto LEDs

TT


Homebrew

The output power of a light source can bedescribed in several ways. Light bulbs aroundthe home and for automobile use tend to berated in watts. The rated output of LEDs isusually quoted in candelas (cd). Early LEDsonly gave out a few thousandths of acandela, so they were rated in millicandelas(mcd). High efficiency modern devices emitseveral thousand millicandelas.

LEDs are very efficient, and will give out light evenwhen drawing miniscule current. The current drawn isdirectly proportional to the voltage applied, soincreasing the voltage will give a brighter light. Thisworks up to a point, but just like a flashlight bulb, toohigh a voltage will burn it out. In practice, I guess it’s acase of the best compromise between getting thehighest light output, while taking the least current. LEDsreach this point at around 20 mA.

Current LimitingWhite LEDs require an operating voltage of 3.6 VDC.For this reason, a two-cell, 3 volt torch is not suitable.On the other hand, connecting an LED directly to athree-cell, 4.5 volt supply will draw far too much currentand fry it!

Some kind of current limiting is needed. The simplestway is just to add a series resistance. Rather thanconnect all the LEDs together and use a single current-limiting resistance to handle the total current, I prefer touse a separate resistance for each LED. This meansthat each one is balanced with regard to the current itwill draw, and physically small resistors can be used.

Before deciding on the level of the limiting resistancesrequired, I had to choose between using 1.2 volt NiCadrechargable cells or standard 1.5 volt alkaline types.Because the torch was for occasional use with a highdegree of reliability, I decided on standard alkaline cells,which have a long shelf life and are readilyavailable.

The output of an LED is proportional tothe current it draws, but it is at its mostefficient while drawing 20 mA. To limitthe current to this level at 4.5 volts, aresistance of 330 ohms was neededfor each one. Resistors with 1/4 wattpower ratings would suffice. I wantedto get as bright a light as possible.After experimenting, I decided to useeleven LEDs, which would fit well intomy proposed design.

If you want to use NiCd batteries (witha nominal voltage of 3.6 volts for threecells), the resistors could be replaced

with wire links. Each LED will then draw about23 mA using newly charged cells, dropping toabout 8 mA at the nominal 1.2 volts level, sono resistors are really needed. If you do this,you must be careful not to ever put alkalinecells into the torch, since their higher voltagemay ruin the LEDs.

Printed Circuit CardI could have used Veroboard (0.1 inch pitch, prototypecopper strip board), but decided that a printed circuitwould be more elegant. CorelDraw software came tothe rescue. A simple design was soon drawn up andphotographed, and a board made (circuit card shownactual size for direct copying).

A printed circuit board starts off life as a wafer-thincoating of copper that is firmly attached to a sheet ofeither paxolin or fibreglass. Fibreglass is much strongerand better suited for homebrew construction. Boardscan be purchased either plain or with the copper sidepre-coated with a light-sensitive emulsion. If plainboards are used, the circuit design can simply be drawnon the board with a special etch-resistant pen. Thisprocess works for very simple designs, but for anythingmore complicated, a photo-resist process is better.

I usually buy off-cuts of plain board in the localelectronics shop. After a rub down with fine wire wool, Ispray them with a light sensitive lacquer, known asphoto-resist. This comes in an aerosol can and is veryeasy to apply. It is sensitive to ultraviolet (UV) light, so itshould not be applied in direct sunlight, and must beused in well-ventilated conditions! After about half anhour of drying, the lacquer is insoluble in the developer(sodium hydroxide).

Exposing the board to ultraviolet light changes theproperty of the lacquer, making it soluble—this is knownas a positive resist. A special light box, housing small

UV fluorescent tubes is normally used forexposure. But bright sunlight can also do

the job, after a little experimenting todetermine the exposure time needed.

After exposure, the resist becomessoluble, except where the drawnpattern has prevented the light fromreaching the lacquer. When the boardis put in the developer, the developerdissolves away the exposed parts,leaving the pattern on the board as athin coating of lacquer. The board canthen be put into a dish of ferricchloride, which eats away theexposed, unwanted copper. Thisleaves the printed circuit pattern

The LED torch’s component overlay.

The LED torch’sprinted circuit card.

WireLink

-Ve Feed

+Ve Feed


Homebrew

beneath the resist, and the boardcan then be dril led to take thecomponents.

Putting it TogetherThe resistors (available from anyelectronics store) were soldered intothe board first. This minimised theheat to the LEDs, which were held in asmall forceps used as a heatsink duringtheir installation. As can be seen on thecomponent overlay (enlarged to showdetails), a small length of wire on thecomponent side of the board is soldered fromthe inner positive connection to the outer ring tocomplete the circuit to the outer LEDs.

Connecting the assembly to the Mag-Litecouldn’t be simpler. The standard torch bulb isheld in with a very robust screw collar. To makethe connection to the torch, I simply broke theglass out of an old bulb, and soldered the two thinflexible wires from the PC board into the metalbulb base (first passing them through the reflectorand screw collar). The base of the bulb is thepositive supply, and the torch body the negative.

The torch doesn’t have to be modified in any waywhatsoever. The PC board sits in the reflector, and theLEDs just press against the plastic top of the torch. Youcan do this conversion on any flashlight designed to runon 4.5 volts, providing that the reflector housing is largeenough to accommodate the PC board and the LEDs.

ResultsThe finished product is fantastic! It doesn’t give a 100yard pencil beam, of course, but that wasn’t the point.The flashlight gives a very even spread of white lightthat is easily bright enough to illuminate a room or tent,or to light your way over the roughest of terrain.

I chose to optimise the LEDs for maximum light output,not being overly concerned with battery life. Higher value

resistances could have been used toreduce current drain, giving longerbattery life. But this would have beenat the expense of the light output.

Reliability and occasional use werethe main requirements. Overall

current consumption at around 220mA may seem a little high, but nowhere

near as much as the standard three-cellbulb at 750 mA. These LEDs are very

efficient. Even when NiCds supplying only3.6 volts are used, they will produce highlevels of light, while reducing the current drainto 10 mA for each LED.

My total cost was around UK£55 (US$75).Expensive, yes, but still about UK£15 (US$23)

less than buying the CC Expedition Flashlight inthe UK. And I ended up with a torch with elevenLEDs rather than seven!

I was lucky enough to buy a twin packcontaining a three C-cell Mag-Lite and a mini

AAA Mag-Lite at the local wholesale warehousefor a total price of UK£19 (US$30). The mini AAAMag-Lite is destined to have a single white LEDfitted to run from one AAA cell via a single

transistor inverter, but that’s another story!

The bonus of using solid state lights is their long life—atleast 100,000 hours is expected. They also give aconstant colour as the voltage of the battery drops, yetthey still give a very useable light source.

The converted torch has been running for several weeksnow, and after many hours of use, I’ve seen nonoticeable drop in brightness. I took it on the firstcamping weekend of the season, arriving at the site bymotorcycle just after dusk. The even spread of light madeit ideal to use while I set up my tent. It also provided areally good interior light, easily bright enough to read by,even when reflected from the roof of the tent.

Easy access to the reflector andconnections made the conversion simple.

LED Torch Costs

Torch Components Costs (UK£) Costs (US$)11 white LEDs, 20 degree, 3,000 mcd £33.00 $49.50Mag-Lite, 3 C-cell 25.00 37.00Photo-resist positive aerosol spray, #YM62S 9.99 14.99Photo-resist developer, 250 ml, #YJ38R 4.99 7.79Fibreglass board, single-sided, 203 x 102 mm (8 x 4 in.), #HX01B 1.99 2.9911 resistors, 33 Ω 1/4 watt 0.55 0.83Wire (scavenged) 0.00 0.00Bulb for connection (scavenged) 0.00 0.00

Total Cost £75.52 $113.10


Homebrew

My flashlight conversion has generated lots of interestfrom friends who’ve seen it. Many of them want to havea go at their own conversion, so it looks like I’ll beetching a few more PC boards before long!

AccessPeter Jones, 2 Highcliffe Dr., Sheffield, England S117LU, UK • 44 114 230 3704 • [email protected]

Farnell, International Distribution Centre, Castelton Rd.,Leeds LS12 2EN, UK • 44 113 263 6311

Fax: 44 113 263 3411 • www.farnell.co.ukLEDs, #993864, Nspw500, 5 mm white

Maplin Electronics, National Distribution Centre, ValleyRoad, Wombwell, Barnsley, South Yorks S73 0BS, UK0870 264 6000 • Fax : 0870 264 [email protected] • www.maplin.co.ukPrinted circuit board, photo-resist, and developer

Comparison test: Stock Mag-Lite on left; Peter Jones’ converted LED Mag-Lite on right.

got solar?...we do!

Call or write for more information and course descriptions.Midwest Renewable Energy Association, 7558 Deer Rd., Custer, WI 54423

phone (715) 592-6595 • fax (715) 592-6596 • [email protected] • www.the-mrea.org

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GUERRILLA SOLAR: The unauthorized placement of renewable energy on a utility grid.PROFILE: 0015DATE: May, 2001LOCATION: ClassifiedINSTALLER NAME: ClassifiedOWNER NAME: ClassifiedINTERTIED UTILITY: ClassifiedSYSTEM SIZE: 100 watts of PVTIME IN SERVICE: 3 months

We are currently renting a two-bedroom apartment on the third floor of a modest building in a major Canadian city. The balcony faces due north, but a corner of it has western exposure, and gets light between noon and sunset.

We built an aluminum and lumber frame for our two 75 wattSolec modules, which are strapped vertically onto the railing of the deck withrope. We have a 100 watt Trace MicroSine inverter. Although Trace no longer sells this inverter,it is still available from the manufacturer in The Netherlands.

We purchased two 12 volt, 75 watt modules because they were less expensive than a single 24 voltmodule rated at 100 watts. We wired the two 12 volt modules in series for 24 volt output. The PVoutput is run through the 100 watt MicroSine inverter. The inverter’s 120 volt output is alwayssynchronized with the frequency of the incoming utility power. This allows clean PV power to flowfreely onto the grid. The inverter’s output is simply plugged into a receptacle, which isprotected by the circuit’s original breaker.

Our main objective in using this system is to reduce our ecological footprint. We figure that ourPVs will displace about 120 KWH of electricity production from a local natural gas plant everyyear. This will save over 65 kilograms of greenhouse gas emissions per year. And it will also helpto reduce emissions of smog-causing NOx and VOCs.

We will never see a financial payback on this investment. Our city has the world’s cheapestelectricity rates, so our savings is less than the cost of a subscription to the local newspaper.This no great loss to us because we would rather be reading Home Power.

We live in a city that is full of renters and people living in apartment buildings. Imagine ifjust 10 percent of our city’s households and businesses were to do what we are doing. Then wecould generate over 10 MW of electrical capacity, displacing over 10,000 tonnes of emissions. Ifwe had the financing programs, incentives, and net metering programs of our neighbors south of theborder, there might be a chance that such a vision could be reached or exceeded. Let’s catch up with the rest of world with distributed renewable energy!

Energy is freely and democratically provided by Nature. Thiscentury’s monopolization of energy by utilities both public and privatethreatens the health of our environment. Solar guerrillas believe thatclean renewable energy should be welcomed by utilities. But utilitiesand governments continue to put up unreasonable barriers tointerconnection, pushing common citizens to solar civil disobedience.

Guerrilla systems do not endanger utility line workers (see HP71,page 58). They share clean, renewable energy with others on theutility grid, and reduce the need for polluting generation plants.When interconnection for small-scale renewables becomes fair,simple, and easily accessible to all, there will be no more need forguerrilla action.

Why Guerrilla Solar?


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Maytag’s model MTB1956DEW,

18.5 Cubic FootRefrigerator/Freezer

Maytag’s model MTB1956DEW,

18.5 Cubic FootRefrigerator/Freezer

Joe Schwartz©2001 Joe Schwartz

ast year, Karen Perez’ mom, Virginia, moved fromNew Orleans to southern Oregon. She lives on-grid. But we still wanted to set up her new home

with the most efficient appliances we could find.

For on-gridders, every KWH savedmeans a lower monthly electricalbill, less pollution, less impact onwildlife, and a reduced threat ofglobal warming. After a bunch ofresearch, we purchased an 18.5cubic foot (0.5 m3) Maytag modelMTB1956DEW refrigerator/freezerfrom a local appliance store.

On-grid, refrigeration is typically oneof the top three household energyconsumers. Off-grid, refrigeration isthe largest electrical load in manyrenewable energy (RE) poweredhouseholds. Efficient appliances arethe basis of any well-designed REsystem. Purchasing an energyefficient refrigerator/freezer makessense for anyone who’s into icecream, cold beer, or whatever elsekeeps you cool and happy.

During the past few years,mainstream appliance man-ufacturers have been introducinghigh-efficiency products. Theseimprovements in efficiency aredriven by federal standards imposedon the manufacturers. Mainstreamappliances typically have severaldistinct advantages over productsproduced by specialty appliancecompanies. These includesubstantially lower cost, widerselection, better features, betteravailability, appliance delivery andset-up, and factory trained servicepeople who come to your house andfix the appliance if it breaks.

DimensionsTo make sure the new Maytag wouldfit in the space available, I checkedthe exterior dimensions beforehand.The Maytag MTB1956DEW is 29-5/8inches (75.3 cm) wide, 66-5/16inches (168.4 cm) high, and 28-7/8inches (73.3 cm) deep.

This refrigerator/freezer has a totalinterior volume of 18.5 cubic feet(0.5 m3). The refrigerator volume is13.08 cubic feet (0.37 m3). Thefreezer volume is 5.38 cubic feet(0.15 m3).

Tested by Home Power

Inside Maytag’s energy efficient and economical refrigerator.

Dual CoolTM FreshnessDesign Slide Controls

Freezer Light

Drop DownFreezerBasket

DairyCompart-ment WithKeeper

Ice Bin

Ice CubeTrays

Ice CubeTrays

TwinExpandable

Freezer Shelf

ExpandableFreezer Shelf

Refrigerator Lights

ElevatorTM Shelf

Multi-Can Rack

Adjusti-TempDrawer

Egg Cradle

Easy Glide/SpillCatcherTM

Shelves

Spill CatcherTM

Crisper Shelf

HumidityControls

Crisper

Safe-Keeper

Keeper

Tall BottleRetainer

Pick OffDoor Bins

Tilt OutDoor Bins

BaseGrille

LL


Things That Work!

We DeliverThe suggested retail price of the MaytagMTB1956DEW is US$869. Mainstream applianceresellers typically work on a high volume and low profitmargin basis. This is due to local competitors that sellthe same appliance models. As a result, we ended uppaying US$780 for Virginia’s new reefer.

We opted to have the new Maytag delivered by thelocal appliance store. Delivery was an extra US$50. Butthis additional cost is well worth it, in my opinion. Anydamage to the appliance during delivery is theresponsibility of the seller. On top of that, the friendlydelivery dudes placed the refrigerator where I pointedmy finger, and unboxed and assembled it.

Assembly included mounting the refrigerator’s handlesand shelving. Because of their familiarity with theappliance, the assembly took them less than tenminutes. If you’re setting up the Maytag MTB1956DEWyourself, detailed instructions are provided in thesixteen page user’s guide.

Energy Efficient Appliance CertificationThe Maytag MTB1956DEW is Energy Star rated.Energy Star is a division of the U.S. EnvironmentalProtection Agency (EPA) that evaluates appliancesbased on their efficiency. In January 2001, Energy Startemporarily suspended its certification of refrigeratorsdue to changing federal efficiency standards scheduledto take effect on July 1, 2001. Energy Star’s newrefrigerator efficiency guidelines will be 10 percentabove these new federal standards. So look forward tothe next wave of energy efficient refrigerators.

Efficiency First!With an energy rating of 485 KWH per year, the MaytagMTB1956DEW was the most efficient refrigerator Icould find in its size and price range. The 485 KWH peryear figure works out to 1.33 KWH per day. Of coursewe decided to see if this figure was for real.

Maytag’s 485 KWH per year figure is based on afreezer temperature of 0 to 5°F (-18 to -15°C), arefrigerator temperature of 35 to 40°F (2 to 4°C), and anambient operating temperature of 65°F (18°C). I set thetemperature controls for both the refrigerator andfreezer at 5 (on a scale of 1 to 10, 10 being thecoldest). These settings gave us an average freezertemperature of 4°F (-16°C), and an average refrigeratortemperature of 36°F (2°C).

Virginia is a New Orleans native and likes to keep herplace hot. The thermostat stays set at 77°F (25°C)!Knowing this would be a challenging environment forthe Maytag to meet spec, I placed a Radio Shackrecording digital thermometer next to the refrigerator.

Minimum recorded temperature was 72°F (22°C).Maximum recorded temperature was 95.7°F (35.4°C).

The Maytag’s energy requirements were recordedusing a Brand model 20-1850 power meter. This watt-hour meter recorded the refrigerator’s consumptionover a 139 day period. Average daily KWHconsumption was 1.40 KWH per day. Peak wattagewas 812 watts (due to the freezer’s auto defrost unit).The appliance’s power factor (PF) was 0.86. Runningwattage varied between 134 watts and 213 watts.

Our recorded daily KWH rate exceeded themanufacturer’s rating by 5 percent. But I still considerthe Maytag MTB1956DEW to be within specifications.The discrepancy is based on the high ambienttemperature in Virginia’s kitchen. Several qualified REdealers reported daily KWH usage for this refrigeratorto be between 0.9 KWH per day and 1.4 KWH per day.

The high efficiency of the unit is largely due to a highquality, single compressor/motor design that cools boththe refrigerator and freezer sections. In addition, afterthe unit is wired, the wall and door cavities are filled

The Maytag MTB1956DEW consumed an average of 1.4 KWH per day in our tests.


Things That Work!

with a liquid insulation that hardens as it cures. Thisprocess results in a fully sealed insulation envelopewith no air gaps.

Most Excellent User FeaturesThe Maytag MTB1956DEW is loaded with greatfeatures. It has two easily accessed thermostats—onefor the refrigerator and one for the freezer. Twovegetable storage drawers include adjustable air slotsto control the humidity levels within the drawers.

If you need to put an oversized item in the refrigeratorportion, a hand-adjusted elevator shelf allows you tochange the shelf height without unloading it. All theshelves in the unit have sealed edges for easy cleanupof spills. The door shelves are designed to handle largeitems like gallon jugs and two-liter bottles.

The Maytag MTB1956DEW is a top-mount model, withthe freezer located above the refrigerator. The freezersection has shelving, a slide-out wire drawer, deepstorage bins on the door, and an ice drawer. Thefreezer can be fitted with an automatic ice-maker kit(part number UKI1500AXX for the MaytagMTB1956DEW).

This reefer is super quiet during operation. Thecompressor/motor is fitted with an acoustic insulationpackage for sound deadening. An automatic moisturecontrol keeps the refrigerator/freezer exterior free offrost and condensation. The freezer is equipped withauto-defrost, keeping its interior free of ice buildup.Both the refrigerator and freezer doors are reversible—they can be hinged from either side depending on thekitchen layout.

WarrantyThe Maytag MTB1956DEW has a full one yearwarranty on parts and labor from the date of purchase.The warranty covers parts but not labor for the secondyear of service. The sealed refrigeration system andcabinet liner (excluding the door liner) are covered by afive year warranty.

Way CoolWe’re super satisfied with the performance and value ofMaytag’s MTB1956DEW refrigerator/freezer. Virginiacommented that she has never had a refrigerator thatkeeps her food so fresh for so long. This is a goodindication of consistent interior operating temperatures.

Mainstream appliances undergo frequent upgrades andmodifications. It’s important to fully research newmodels and their specifications before you make yourpurchase. Check out the Web sites listed in the Accesssection of this article for sources of current energyefficient appliance information.

Things That Work! CriteriaThe products reviewed in Things that Work! must meetthree criteria:1. The product must meet its manufacturer's

specifications.2. The product must be durable and last in actual

service.3. The product must offer good value for the money

spent on it.

The reviewed equipment is not necessarily the bestproduct for all applications.

AccessJoe Schwartz, Home Power, PO Box 520, Ashland, OR 97520 • [email protected] • www.homepower.com

Maytag Customer Service, 240 Edwards St., Cleveland,TN 37311 • 800-688-9900 (U.S.) • 800-688-2002(Canada) • Fax: 641-787-8676 • www.maytag.com

Energy Star, U.S. EPA (6202J), 1200 PennsylvaniaAve. NW, Washington, DC 20004 • 888-782-7937Fax: 202-775-6680 • [email protected]

American Council for an Energy-Efficient Economy,1001 Connecticut Ave. NW Suite 801, Washington, DC20036 • 202-429-0063 • Fax: 202-429-0193www.aceee.org • Web list of energy-efficientappliances, and publisher of Consumer Guide to HomeEnergy Savings, now in its seventh edition, by AlexWilson, Jennifer Thorne, and John Morrill

This Maytag looks like any

other refrigerator,but it is

super-efficient.

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Ilive in a canyon near Santa Barbarathat suffers from power failures fromwinter winds. Since California

deregulated their utilities, the time ittakes for downed power lines to berepaired has increased. I recentlyinstalled a pair of Trace DR1524inverter/chargers as an emergencybackup system in my grid-connectedhome. The next logical step was to setup a low-cost propane generator.Although there are a lot of inexpensive gasolinegenerators available, I wanted to have a propanegenerator because of the storage and safety issueswith gasoline. The propane generators that I found wereconsiderably more expensive than gasoline models.

Generator & KitI found a Web site with propane conversion kits for sale,and another with generators. I ordered a 5 KWgenerator with an 8 hp Tecumseh engine for US$420,

and then ordered the conversion kit. Later it turned outthat the generator was on backorder, so I found a morepowerful generator at my local Costco store for US$399and canceled my online order.

The generator I bought was a Generac 5 KW with 6.25KW surge. It also has a Tecumseh engine, but a 10 hpmodel instead of 8 hp. The propane conversion kit that Ipurchased for the 8 hp engine was designed for thisengine too.

The conversion kit recommended running the generatoron gasoline for an hour to seat the piston rings forproper break-in of the engine. When I started it up to dothis, I realized why it was so inexpensive. It was so loudthat you could hear it throughout the entireneighborhood—the noise level was obscene.

Luckily I found another Web site that sold a Tecumseh“low tone” muffler for US$60. This made the noise levelsomewhat bearable. If you do a conversion with anengine like mine, I would highly recommend that youbuy this quieter muffler.

ConversionThe propane conversion process took about threehours. It seemed a little complicated after reading theinstructions, but the process was not difficult. It involved

Herb Levitin ©2001 Herb Levitin

Herb Levitin’s generator converted to propane, with the new tank in position.


Generator

removing the carburetor, float bowl, and main jet. Themain jet passage was drilled out, and the propaneadapter was inserted into the carburetor. Several holesin the carburetor were sealed with the silicone sealantprovided in the kit.

The conversion kit came with adapters for the roundtube frame of the generator I originally ordered. I used a3/4 inch PVC electrical elbow and drilled a 1/4 inch (6mm) hole in it and the frame to mount the regulator.Ordering the kit for a square tube generator would haveeliminated this extra step.

As the picture shows, I mounted the five gallon (19 l)propane tank on the shelf that held the gasoline tank.The shelf will also hold my 500 watt Honda gasgenerator, which is very quiet. I plan to run the Hondagenerator to charge the batteries at night if necessary.

The “low tone” muffler arrived and was installed, and Iadjusted the idle adjustment on the regulator. Iconnected two 1,500 watt heaters to the generator as atest load and watched the generator run for 30 minutes.I’m guessing that a standard 5 gallon propane tank willrun this generator for over eight hours at full load.

I have a 24 VDC, 510 AH battery bank, monitored by aBogart Engineering TriMetric amp-hour meter. Thebattery bank is connected to two Trace DR1524inverters with a stacking cable. The entire house can bepowered by these inverters, except for the washer anddryer. I expect about a ten to twelve hour run time withthe inverters, which will allow me to run the generatoronly during the day.

Reliable BackupSince deregulation in California, power outages aregetting longer. It seems that Southern California Edisonhas reduced its staff, and repair times are now basedon the number of affected users, not how long thepower has been out. Minor failures such as a downedline seem to take much longer to get repaired thanbefore deregulation. We have already had several one-hour outages because of the stage three poweremergency. We also have had several twelve hourfailures over the last three years.

My generator, with its propane conversion, will give mereliable backup power through these outages.Dovetailed with the inverters and battery bank, it shouldbe able to keep my critical loads, such as my Takagitankless water heater and hydronic house heatingsystem operational. I would also like to install a PV grid-intertie system, before California's Buydown program(see HP82, page 48) runs out of funds.

AccessHerb Levitin, 1604 State Street, Santa Barbara, CA93101 • 805-963-4864 • [email protected]

U.S. Carburetion Inc., HC 79 Box 130, Canvas, WV26662 • 800-553-5608 or 304-872-7098Fax: 304-872-3359 • [email protected] • Propane conversion kit

M&D Mower, 32045 N. Roundhead Dr., Cleveland, OH44139 • 440-914-1252 • Fax: 877-335-8999 or 440-232-9962 • [email protected] • “Low tone” muffler

Generator Conversion Parts

Item Cost ($US)

Generac PP5000T generator, 5 KW $399.95Conversion kit for Tecumseh engine 159.00Low tone muffler 59.95Tank regulator kit PGK-6, with 6 foot hose 29.95Propane tank 22.88

Total $671.73

Conversion kit with Herb’s custom mount.

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Wrench Realities

The GreatWelding CableDebate Continues

Drake Chamberlin©2001 Drake Chamberlin

Welding cable has been usedsuccessfully for batteryinterconnects for decades.

Many retailers of renewable energyequipment use welding cable for pre-made battery interconnects and invertercables. It has not, however, beenpermitted in areas where the NationalElectrical Code (NEC) is enforced.Many renewable energy (RE) workers consider weldingcable the favorite material to use for connectingbatteries and inverters. It is readily available andrelatively inexpensive. It is extremely durable andflexible. It is also very resistant to being damaged bybattery acid.

What the Critics Say About Welding CableIn Code Corner, HP82, John Wiles stated that manycables do not have “any marks or labeling that ensure

that they have been tested and evaluated for safety inany application.” These cables are available from “autoparts stores, hardware stores, building supply stores,and welding shops.” He also said that the UnderwritersLaboratory mark needed to be on the cable. Without theUL symbol of approval, Mr. Wiles notes, the suitability ofa cable cannot be determined.

John continues the argument by saying that without thismarking, it cannot be known if the manufacturer cutcosts in the construction of the cable. The cable’scopper might have higher resistance. The sheath of thecable might crack or catch fire more easily. Additionally,a UL mark on a cable guarantees that the product hasbeen thoroughly evaluated by a competent, nationaltesting laboratory. Without a UL marking, the cable mayor may not be adequate for any particular application.

UL-Approved Welding CableI recently did some research, and found that manybrands of welding cable are indeed UL approved.According to the UL Web site, however, there will not bea UL mark on the sheath of the cable. The listing markof Underwriters Laboratories is only to be found “on theattached tag, coil, reel, or smallest unit container inwhich the product is packaged.”

Listed welding cable is in compliance with NEC Article630, Part E, which deals with the secondary circuits ofelectric welders. It can be rated at 60 to 90°C (140 to195°F), and 100 or 600 volts.

The listing mark on the tag that comes with theseproducts includes the name or symbol of UnderwritersLaboratories, together with the word “listed.” It alsocontains a control number and the product name,“welding cable.” The temperature and voltage ratingsmay be marked on the sheath, as well as on the tag. Ifthey are not marked, the temperature rating is assumedto be 60°C, and the voltage rating 100 V.

When the cable has the higher voltage and temperatureratings, markings will appear on the sheaths. Themarkings of 600 volts and 90°C will be printed on theinsulation. The UL listing mark, however, will notappear. UL-listed welding cable comes in sizes from #8AWG to 250 kcmil (8 to 127 mm2), in flexible strandedcopper. The individual strands are #34 to 30 AWG (0.02 to 0.05 mm2).

John Wiles says that cable that does not bear the ULmarking cannot be verified to be a tested, safe, anddurable cable. Welding cable, however, does not have aUL stamp on its sheath, even when it is l isted.Information about UL-listed welding cable can beobtained from the UL Web site. Specific information canbe obtained from the manufacturers, whose addressesare provided on the site.


Wrench Realities

The Acid TestMy article in HP80 (page 84)documented the effects of batteryacid on some welding cableinsulation, and certain other types ofcable insulation. The welding cablewe tested was unharmed. The 1996NEC required battery cables to beacid resistant, and to be chosenfrom Article 400. This created acontradiction, since there were nocables listed as acid resistant inArticle 400. The 1999 NEC nolonger requires cables to be acidresistant. Theoretically, this isbecause plastic and rubberconductors are considered to beinherently acid resistant.

In the RE Lab’s “acid test” of variouscables, type THHN/THWN cable showed a tendency todissolve in battery acid. Section 310-13 of the NEClists this cable as “heat resistant thermoplastic.” Yet itslowly melts in battery acid. It appears that acidresistance might still be a reasonable requirement forbattery cables. UL-listed “Super ExCelene®” weldingcable is rated for acid resistance.

Welding Cable for Batteries & InvertersWelding cable has traditionally been a favorite materialto make battery interconnects. In early systems, weldingcable was routinely used to connect battery banks toinverters. Welding cable was often run from batteryboxes to inverters without conduit. Although not codecompliant, this practice is still common today.

This seemed appropriate, since welding cable isexposed to physical contact when used with arcwelders. The cable is energized with similar voltages inRE systems as in welding operations. The electricalpotential in both applications is usually DC.

Welding cable is very robust. It may be in frequentcontact with molten metal. It is exposed to a widevariety of mechanical impacts. It can lie on shop floorswith scraps and shavings of metal, where it can be runover by forklifts and automobiles.

Welding cable is safe to use. Arc welders are used inthe construction of metal frame buildings. A truck-mounted welder may be several stories below thelocation where the arc is struck with the welding rods.Welding cable carries the current from the weldingmachine to the point of use. Welders and other workersstanding on conductive metal framing may be exposedto the cable. Similar situations exist for weldingoperations on metal towers.

Welding cable is used for applications that are muchmore abusive and potentially dangerous thanrenewable energy installations. At least some varietieshave been demonstrated to be acid resistant. Weldingcable is certainly an adequate product for use withbatteries and inverters.

Permitted CableBattery interconnections are required to be made withflexible cables as identified in Article 400 of the NECWelding cable is not listed in Article 400. Interestinglyenough, some cables that we are permitted to use,such as finely stranded USE-RHH-RHW Hypalon diesellocomotive cable, are not identified in Article 400 either.Since both types of cable are UL listed, and neither areidentified in Article 400, there seems to be little logic inallowing one while forbidding the other.

Many suppliers sell battery interconnects made fromwelding cable. RE systems are still being rejected bylocal inspectors because welding cable is used. Theacceptance or rejection of a system is ultimately basedon the code interpretation of the particular inspector. If asystem is rejected because of the use of UL-listedwelding cable, certification and specifications of thecable can be obtained from the manufacturer. Theinspector may accept the cable based on thisinformation. It would be helpful if wrenches wouldcontact Mr. Wiles with their concerns about the weldingcable ban.

This investigation into welding cable has beenconducted as an activity of the Renewable Energy Lab,as described in HP80, page 84. Chris Sinton of AlfredUniversity is actively seeking funding under the name“Renewable Power Installers Advocacy Program.”

A welder throws robust welding cables down from a tower job.

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Wrench Realities

AccessDrake Chamberlin, Electrical Energy Contracting andConsulting, 3138 Lyle Ct., Denver, CO 80211 • [email protected] • RE Lab Web site:www.eagle-access.net/solar

See Web site for listing of RE Labmembership.

Chris Sinton, Acting Director, Center forEnvironmental and Energy Research,Alfred University, Alfred, NY 14802 • 607-871-2642 • Fax: [email protected] • http://ceer.alfred.edu

UL Web site: www.ul.com/database

To find listed welding cable, search by thekeyword "welding cable.” For info on ULlisting tags click on "ZMAY.GuideInfo."

John C. Wiles, Southwest TechnologyDevelopment Institute, New Mexico StateUniversity, Box 30,001/ MSC 3 SOLAR, LasCruces, NM 88003 • 505-646-6105 Fax: 505-646-3841 • [email protected]/~tdi

National Electrical Code and NEC areregistered trademarks of the National FireProtection Association. The 1999 NEC andthe NEC Handbook are available from the

NFPA, 11 Tracy Dr., Avon, MA 02322 • 800-344-3555 or 508-895-8300 • Fax 800-593-6372 or [email protected] • www.nfpa.org

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They Do It on RE

Solar-Powered Glass ArmonicaWilliam Wilde Zeitler

©2001 William Wilde Zeitler

Ben Franklin (1706–1790) wasconsidered one of the world’sforemost experts on electricity in

his day, and is known for manyinventions. What isn’t as well known isthat Franklin’s favorite invention was amusical instrument.He called it the “glass armonica” after the Italian wordfor “harmony.” It works on the wet finger around thewine glass principle. Franklin’s idea was to nest a set ofwine glasses inside of each other, one for each note, allmounted on a rotating spindle. Then you could play itwith wet fingers, almost like a piano.

Otherworldly SoundThe instrument became very popular in the late 18thcentury—even Mozart and Beethoven wrote music forit. But around 1810, they decided that its otherworldlysound would wake up the ghosts, so it was banned. It’sbeen on the Endangered Musical Instrument List eversince. For sound and video samples, and much morehistory, see my Web site.

I’ve been a musician since I was five, I’m a classicallytrained pianist, and I have a degree from the CaliforniaInstitute of the Arts in harpsichord. One day I trippedover a CD of “music by Mozart for the glass armonica.”Having no idea what a glass armonica was, I took ithome, and that was it. I had to play this! I found thatFinkenbeiner Inc. was blowing the glasses again, andoff I went. I know of only a dozen performers in theworld. I do about 75 performances a year, and havethree CDs, with number four due out this summer.

Not an Energy HogFranklin made his spindle rotate with a foot treadle. Themain reason I opted for a motor instead of a foot treadleis that I can play much better standing than sitting. The1/28 horsepower motor that turns the spindle draws awhopping 16 watts (measured at the wall). But when Iplay outdoors at weddings or festivals, I often don’thave access to an AC outlet.

The instrument is already set up to use 110 VAC, so thesimplest thing to do was to get an inverter and a deep-cycle battery. The smallest inverter I could find at thelocal RV supply was 75 watts. With the smallest batteryavailable at Costco (90 amp-hours), I ’ve runcontinuously for two to three days without a recharge(we also run a cash register with the samebattery/inverter setup).

REmarkable, Unusual, & Inspiring Usesof Renewable Energy Technologies

REmarkable, Unusual, & Inspiring Usesof Renewable Energy Technologies

William Zeitler plays a solar sonata.


They Do It on RE

Mobile Solar MusicBut I was concerned that I wouldn’thave enough juice to make it throughlonger festivals, so I got a solar-electric (PV) panel to add to thesystem. The panel is a SolarexMSX-30 Lite, rated at 30 watts. It’s atough, bendable panel, which isperfect for taking on the road. At24.4 by 19.6 by 0.6 inches (62 x 50 x1.5 cm), it’s still easy to find spacefor it in the truck (along witheverything else one needs for afestival).

The solar panel is only connectedwhen the battery is under load, so Idon’t have to worry aboutovercharging the battery. I hook thesolar panel up to the battery inparallel with the load, with no chargecontroller. I wired a diode in serieswith the solar panel to preventdischarge through the PV when thesun goes behind a cloud.

I suppose I could get a largerbattery, or find another way to runmy instrument. But there’s justsomething right about a solar-powered glass armonica. I think BenFranklin would approve!

AccessWilliam Wilde Zeitler, PO Box 33119,Seattle, WA 98133 • 877-ARMONICA or 206-364-8042Fax: [email protected]

G. Finkenbeiner Inc., 33 RumfordAve., Waltham, MA 02453 • 781-899-3138 • Fax: [email protected] armonica manufacturer

Do you have an uncommonapplication of renewable energy inaction? We’d like to share it withHome Power readers. Send yoursubmissions [email protected]

CHEAPESTSOLAR.COM


he relative handful of electricvehicles (EVs) on the roads todayare surrounded by a cloud of

smog produced by the vast majority ofcars, which still burn petroleumproducts for fuel. But the EVs areobscured by another kind of cloud aswell. It is a cloud of myths andmisinformation that permeates thepublic consciousness.Some of this has been deliberately spread by, shall wesay, dark anti-EV forces. But most of it is simply theresult of honest but faulty assumptions. Some of themisconceptions make EVs look bad, and some makethem look too good. Let’s examine the most commonmyths and misconceptions about EVs, and comparethem to the real facts.

Myth #1: An EV’s Range is Too ShortWhen asked how long a man’s legs should be,Abraham Lincoln replied, “Long enough to reach theground.” How long is a long enough range for an EV?That depends on what you need to do with it.

Ninety percent of the cars in the United States travelfewer than 25 miles (40 km) a day. A typical home-builtelectric conversion can get 50 miles (80 km) or more ona charge. Some can get quite a bit more. Even a very

modest, low-performance conversion will get 20 to 25miles (32 to 40 km).

Range is a function of vehicle weight andaerodynamics, battery pack size, road conditions andterrain, traffic flow, and driving style. You need toexamine your real-life driving patterns, and then seewhether one type of EV or another has long enough“legs” to do the job for you.

“Well, sure, most of the time I just drive to work andback. But what about when I want to go on vacation?”Again, statistics show that most households have morethan one vehicle. Does yours? Many people have asmall economical car for daily local use, and a biggervehicle for long trips. The small one could be electric.

An electric car is like a microwave oven. It can’t replaceall the functions of a conventional oven. But there aresome things that it does much better than the traditionaloven, and it does some things the old oven can’t do atall. Despite its “limitations,” most households have one,and use it a lot.

Myth #2: EVs Are SlowWhen people think of EVs, they think of golf carts, orsome tiny, funny-looking little thing that their eccentricold neighbor drove in the 1970s. They think 25 or 35mph (40 or 55 kph) is the best it can do.

This is absolutely not true. Even a very basicconversion can do 55 to 65 mph (88 to 104 kph), andsome can do more than 90 mph (145 kph). These arenormal street cars, not tricked-out race cars. Like

Clearing the SmokeClearing the Smoke

Electric Vehicle MythsElectric Vehicle Myths

TTShari Prange ©2001 Shari Prange


GoPower

range, speed will be related to the vehicle weight andshape, battery pack size, and terrain.

“Yeah, but how long does it take to get up to thatspeed?” To paraphrase an old racing saying, “Speedcosts amps. How fast do you want to go?” Dependingon how the car is designed, it can come close to, oreven exceed acceleration for a normal gas car.Acceleration is determined by vehicle weight andbattery pack size, as well as battery type and controllertype.

Do you simply want to be able to merge safely onto thefreeway? Or do you have some unresolved emotionalissues that require leaving smoking patches of rubberat the stoplight? There is a very active organization ofelectric drag racers who will be delighted todemonstrate this for you. The choice is yours.

Myth #3: If I Run Out of Juice, I’m StuckFirst of all, your car will (or, at least, it should) havesome kind of gauge to let you know how much chargeyou have left. This may be a voltmeter, a watt-hourmeter, or just a plain old state-of-charge gauge thatreads from “Full” to “Empty,” just like a gas gauge. Thisdoes not have to be rocket science.

Second, you need to know that an EV does not juststop dead like a gas car does when it runs out of gas.As you get very low on charge, you will notice a slightsluggishness, especially on hills. This will graduallyincrease over the course of several miles. If you havemiscalculated badly enough, you will eventually need topull over to the side of the road.

Unlike the driver of a gas car out of juice, however, youdo not need to get out your cell phone and call AAA, orstart hitchhiking. Instead, you simply let the car rest fora few minutes. You can watch the needle of your state-of-charge gauge rise as the batteries recover a portionof their charge. You can now drive a little farther. Ifnecessary, you can repeat this process several times toget home, although it’s not recommended to make ahabit of it.

Myth #4: EVs Just Move the Pollution SourceThis is a very prevalent myth. People will give you that“Gotcha!” knowing smirk and say, “Of course, EVs justtransfer the pollution from the tailpipe to the powerplant.” Again—not true. This particular myth hasmultiple fallacies in it, so let’s take it apart piece bypiece.

Let’s say you have a gas car and an electric car sittingside by side at the stoplight. The electric car is cleanerthan the gas car, even if you include the pollution fromthe power plant—even if it’s a nasty coal burning plant.That’s because it’s much easier to control pollution from

one large stationary smokestack (where it’s possible toinstall giant scrubbing equipment) than it is to control amillion tiny mobile tailpipes. Power plants are constantlymonitored and get regular maintenance. Far too manycars are only checked every year or two when the lawrequires it, and only get maintenance or repairs whensomething makes noise or falls off.

But is it really fair to compare power plant emissions forthe EV to tailpipe emissions for the gas car? Whatabout pollution caused by the oil refinery, and the tankerships and trucks? (This is the part where the smirkmelts into sheepish realization.) In a full (oil) well-to-wheel comparison, the EV comes out even furtherahead.

Myth #5: Electric Power Is Less EfficientA similar myth is that EVs are less efficient in their useof energy, because there are substantial losses in thepower transmission lines. Well, yes, there are. But thereare even greater losses in the running of an internalcombustion engine. A gas engine needs a radiator tocarry off the excess heat; otherwise the engine willdestroy itself. All that heat represents wasted energy.

Again, if you look at a full well-to-wheel comparison,almost 50 percent more energy makes it to the wheelsof the EV than to the wheels of the gas car.

Myths #6-#8: In An Accident, An EV Will...People are afraid of things that are unusual, or that theydon’t understand. EVs fit both criteria. People are afraidthat, in an accident, an EV will explode, or electrocutethem, or melt them like the Wicked Witch of the West ina pool of battery acid. In fact, some people are afraid todrive them in the rain, or to wash them, for fear ofgetting electrocuted.

When gas cars first came out, there were similarsentiments. Where we live in Santa Cruz, there is anearly American dairy ranch that has been restored andopened as a historical park. The tour guide explainsthat the garage is situated way over there because thelady of the house was skeptical of this new-fangledautomobile. She wanted it kept far from the house sothat if it blew up in the middle of the night, it wouldn’tburn the house down.

Sound silly? Well, maybe a little. But do you realize thata single gallon of gasoline has the explosive power oftwenty-two sticks of dynamite? Yet people routinelystrap their infants into these contraptions and drivearound at high speeds with a tank full of ten or twentygallons of this stuff, often mere inches away from allthose scalding hot engine and exhaust parts.

My point here is not to slam gas cars, but to point out acommon perceptual error. We tend to exaggerate the


GoPower

dangers of something new andstrange. At the same time, weconveniently forget that familiar itemswe use without a second thoughtevery day have comparable dangers.If we are going to comparetechnologies fairly, we have to try tolook at them both from a similarperspective. So let’s look at thesefears one at a time.

Electrocute MeTo get a shock, you have to come intocontact with an electrical circuit. Anormal car uses the metal chassis asthe ground portion of the electricalcircuit. An electric car’s battery packdoes not. It is a “floating,” or isolatedsystem. In fact, various componentson the car have built-in ground fault detectors, so thatthey will not operate if there is battery pack currentpassing through the chassis, even in milliamps. The onlyplace to contact the circuit is directly at the batteries orcomponents under the hood, or at the cable ends.

These cables do not normally enter the passengercompartment, or if they do, it is only minimally toaccommodate a circuit breaker. If your car is damagedbadly enough to have bare cables somehow protrudinginto the cabin, the circuit is probably destroyed innumerous places, and you’ve got much biggerproblems to worry about.

And remember that circuit breaker we just mentioned?That’s one safety device that will trip automaticallyunder high current, or can be flipped manually to breakthe circuit. There should also be fusible links, which willblow automatically in case of a short, and break thecircuit. Car washes, rain, and normal road splash arenot hazards, and will not cause you to get shocked.

ExplodeIn the movies, all cars in accidents explode. In real life,it seldom happens. There is nothing inherentlyexplosive about an electric car in normal use. The onedanger comes from hydrogen gas, which is given off bythe batteries under severe abuse or during charging.Hydrogen is lighter than air, and if the battery area isproperly ventilated, it will quickly rise and dissipate. Apretty strong concentration of hydrogen is neededbefore it reaches explosive levels.

The most common situation for a battery explosion isnot in an EV at all, but in an old VW Beetle. The batterycompartment was out of sight and completelyenclosed—a perfect recipe for neglected maintenanceand an accumulation of gas. It was also located right

under the rear seat. You lean into the back seat toretrieve a package, put your knee on the seat, thesprings contact the battery posts and make a shortcircuit, and ka-pow!

This resulted from poor design, not from inherentdanger in using batteries. Sensible EV designovercomes the risks, and eliminates the chance ofexplosions.

Burn Me With AcidThe acid in a battery is not like the stuff in the movie“Alien” that instantly ate through everything in its path.In fact, it is not uncommon for people working on theircars to splash themselves with battery acid and noteven notice. They don’t realize it until the next time theylaunder their blue jeans, and the weakened cottonfibers melt away, leaving a series of holes. The jeanshave holes in them, but not the person.

If you know you’ve been in contact with battery acid, ofcourse it’s a good idea to wash it off as soon aspossible, but you might not even feel it. It takes sometime before it starts to irritate the skin. In fact, gasolinesplashed on your skin and not washed off can lead tosome pretty nasty skin irritation.

In gas cars, the battery is often in the left front corner ofthe car—the place most likely to be contacted in acollision—and minimally secured. Yet we have spokento numerous firefighters, paramedics, and tow truckdrivers who are intimately involved with accidents on adaily basis. Battery acid spills are not a significanthazard at accident scenes.

Sure, an EV has a lot more acid on board. But it iscarried in lots of small cells. You would have to break alot of cells open to get any significant amount of acidspilled.

In a full “well-to-wheel” comparison, EVs are more efficient and less polluting than internal combustion cars.


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We had a graphic demonstration of this about eightyears ago. Our electric kit car is a fiberglass body on aVW chassis. In other words, a little more protection thantissue paper. It was hit by an older American Buick thatnailed it dead on the battery pack, right behind thedriver. The impact pushed the EV sideways across anintersection, over the curb, and into a signpost.

No one was hurt. The Buick scraped its bumper a little.The kit car body was shattered. Three wheels werebent. One battery box cracked because the frame railsupporting it broke and dropped the box on the ground.Another box split at the seams. Not a drop of acid wasspilled.

In another accident, an electric Rabbit belonging to acustomer was hit by a Suzuki, right in the middle of theVW grill. The impact was also right in the middle of thefront batteries, which were resting in racks only, notenclosed in boxes. The Rabbit lost the acid from onecell of one battery. The Suzuki, on the other hand, splitits oil pan and dropped all its oil on the road.

There’s actually a safety advantage to all those batteries.In the early days of crash testing gas cars, testing wassometimes done with the batteries drained, becausepeople were concerned about acid spills. Then it wasnoticed that the cars with full batteries did better in thecrash tests. The liquid absorbs some of the impact, justlike those water-filled barrels along the highways. If theliquid in a single battery made a noticeable difference in agas car crash, think about the impact absorption of six oreight batteries under the hood.

In fact, there have been a few instances of racing EVscrashing straight into a cement wall at highway speeds.There have been no explosions, fires, electrocutions,acid burns, or even injuries to the drivers.

Myth #8: Dead Batteries Will Pollute LandfillsWhen you buy a new battery for your car, the seller willwant the old “core” in return, and will charge you a fee ifyou don’t turn it in. For a whole pack of EV batteries,this can really add up, so it makes sense to turn thecores in. They are then deconstructed, and thecomponents are recycled into new batteries. In fact,lead-acid batteries are one of the most highly recycleditems in the country, with a rate of 99 percent.

Magic Carpet MythsHere’s where the myths turn in the opposite direction.Instead of making EVs into monsters, these myths try toturn them into magic carpets. Unfortunately, there is nosuch thing as a free lunch, or perpetual motion. Peoplethink they can get free energy and unlimited range ifthey only attach the right device to an EV. So let’s lookat a few of these pipe dreams.

Myth #9: Solar PanelProbably the most popular of these is the solar-panel-on-the-roof. However, PV efficiencies are so low thateven with a PV-covered roof, the average EV sitting infull sun all day long would only gain about 5 miles (8km) worth of electricity. Now, if you drive less than fivemiles a day and you live in Arizona, or if you drive 15miles (24 km), but you only do it twice a week, thismight work for you. For most people, it would not beenough to justify the cost of the panels. Solar chargingis generally only practical from a large stationary array.

Myth #10: GeneratorThe other top contender is the Honda-generator-in-the-back-seat. Briefly, generators are noisy, they vibrate,and they re-introduce the fuel and maintenance issuesof internal combustion vehicles. They also can produceas much pollution as thirty gas cars.

For all of that, they will probably only produce enoughenergy to get you an extra ten miles (16 km) of range.An EV, simply cruising, will draw 20 KW of power.That’s DC power. Most generators are rated for ACoutput. Converting that to DC reduces it considerably.The math just is not favorable.

Myth #11: WindmillThen there’s the ever-popular windmill-on-the-roof. Oron the axle—doesn’t matter where. A similar scheme isthe alternator hooked to the axle or motor shaft. Theproblem for both of these is the same. The energy theycapture is not really “free.” It has to come fromsomewhere, and where it comes from is the car’smomentum. In other words, the harder you try to turn awindmill or an alternator to charge the batteries, themore you slow down the car.

If you’ve ever ridden a bicycle with a generatorheadlight, you know how much harder it is to pedal withthe drag of the generator on. If you want to try a windexperiment, mount a small fan on top of your bicyclehelmet and go for a ride. See what the wind resistancedoes to your energy level and speed. Not to mentionwhat the sight does to your reputation in theneighborhood.

Just the FactsWhen the smoke finally clears, you can see that EVsare not a magic free ride, but neither are they thecrippled, dangerous frauds that they are often portrayedto be. Most misinformation is a result of starting fromassumptions instead of checking actual numbers, or notmaking apples-to-apples comparisons.

An electric vehicle does one kind of driving particularlywell. This happens to be the same kind of driving thatmost cars spend most of their time doing. When theyare fitted to the proper use, EVs are very reliable,


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practical, and clean. Once you get past the myths andmisconceptions, it’s as clear as day.

AccessShari Prange, Electro Automotive, PO Box 1113-HP,Felton, CA 95018 • 831-429-1989 • Fax: [email protected] • www.electroauto.com

Electric Auto Association, 2 Smith Court, Alameda, CA 94502 • 510-864-0662 • Fax: [email protected] • www.eaaev.org

California Energy Commission, 1516 Ninth Street, MS-29, Sacramento, CA 95814 • 916-654-4287 www.consumerenergycenter.org/transportation/afv/ev.html

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GoPower

Why Convert A GasCar To Electric?Mike Brown ©2001 Mike Brown

“I have an older compact car that just failed itssmog test. What are the benefits of converting it toelectric power instead of just scrapping it?”

A gentleman at an electric vehicle show asked me thisquestion last weekend. It’s one I get asked often, so Ithought it would be a good question to answer in detailfor Home Power readers as well.

The gentleman had owned the car—a 1989 FordEscort—since it was new, and he liked it. The car’sbody and interior were in good shape, and it was ingood mechanical condition. The car weighed less than2,800 pounds (1,270 kg; which we consider to be themaximum a car or truck can weigh and make asuccessful conversion). It also had a manualtransmission, which is essential. In addition to thesethings, we knew that the car was popular forconversions because we had sold a lot of motor-to-transmission adaptors for it.

So given that the car would make a good conversion,what are the benefits of converting it? Let’s look at thebenefits to the environment first.

Cleaner AirThere are many reasons that converting a gas car toelectric makes environmental sense. An EV is cleanerthan a gas car, even if you include emissions from thepower plants. Of course, some of the cleanest powercomes from hydro plants. EVs charged fromhydropower produce 98 to 99.9 percent lessgreenhouse gases, and 99.9 percent less of all the non-greenhouse gases combined.

On the other end of the spectrum, the dirtiest power isfrom coal. EVs charged from coal plants produce 55 to59 percent less greenhouse gases, and 80 to 92percent less non-greenhouses gases than a gas car.Natural gas electricity falls in between these twoextremes.

EVs are also cleaner over time. The power companiesare required by law to continuously upgrade their plants

to meet tighter emission standards. This means that thelonger an EV is driven, the cleaner it gets. In contrast,as a gas car ages, its mechanical condition deterioratesand its emissions go up.

Also, most gas cars are driven 25 miles (40 km) or lessin a day, and spend most of their time idling and in stop-and-go traffic (which means they are not fully warmedup). Their emissions are the highest in these conditions.In contrast, the EV sitting at the stoplight is notproducing any emissions at all. Instead of idling, theelectric drive system simply turns off.

Cleaner Water & EarthAn EV reduces other types of pollution as well. Mostcars drip a little oil, coolant, and other fluids as they godown the road. These things create the dark stains onthe parking lots and the black stripe down the center ofthe roads. When it rains, these fluids are washed intothe storm drains and from there into the nearest river,lake, ocean, or into the ground, and then into the watersupply.

In addition to being cleaner in use, the EV is alsocleaner to maintain. A gas car needs regular engine anddrive train maintenance, which produces hazardouswastes in the form of used oil and oil filters. When thecoolant is replaced, the old coolant must be treated as ahazardous waste if it cannot be recycled. Things likefuel filters, air filters, spark plugs, and other tune-upparts are not recyclable, so they end up in a landfill. AnEV doesn’t use any of these items, so there are no oldcontaminated parts to create disposal problems.

In fact, the only things that are periodically replaced onan EV are the batteries. This usually happens afterthree or four years of use. Even then, there is very littlenon-recyclable waste involved, since the batteries are99 percent recyclable. This is not only good for theenvironment, but also for the pocketbook. If new leadwere used to make batteries instead of the recycledlead, batteries would cost much more than they do now.

EVs help reduce the waste stream in even more subtleways. When a gas car is sent to a wrecking yard, it isstripped of its usable parts for resale, and all therecyclable materials are reclaimed. But 30 percent ofthe car—the glass, rubber, upholstery, and most of theplastic—ends up in the landfill. In addition, when thenew cars that replace the scrapped ones aremanufactured, several tons of waste are generated inthe manufacturing process. Doesn’t it make more senseto recycle a whole car that is in good shape except forits tired or dead engine?

Save EnergyThere are several energy-saving reasons that makeconverting a gas car to electric power a practical idea.


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The efficiency of an electric drive system is the first.Let’s follow the energy trail from when the energysource is removed from the ground—coal mined, oilpumped etc.—to when the wheels turn and the carmoves down the road.

If the car is gas powered, 11 percent of the energy thatcame from the ground remains to turn the wheels. If thecar is an EV, 17 percent is left to propel the car. TheseU.S. Department of Energy figures take into account allthe energy used to produce the fuel and transport it tothe car, in the case of a gas car. In the case of an EV, thetransmission losses incurred in sending the electricityfrom the power plant to your charger outlet are included.

This energy saving is true of all EVs, either factory builtor conversions. Recycling a used gas car by convertingit to electric power instead of replacing it with a new carbrings its own unique energy savings. Take all thevarious types of energy used in the manufacture of anew 2,500 pound (1,130 kg) car and convert them to acommon form of measurement (the British thermal unit,or BTU) and total them up. It works out to about 120.7million BTUs.

Next, use the number of BTUs in a gallon of gas(125,000) to calculate the number of gallons of gas(965) the total manufacturing energy represents. Dividethe 965 gallons of gas by the 506 gallons a year theaverage driver uses.

You’ll find that the 2,500 pound car can be driven foralmost two (1.91) years on the energy that it took tobuild it. This is a very real reason to recycle a gas carby converting it to electric power instead of replacing it.Another smaller but satisfying energy savings comeswhen the EV is stopped in traffic. The only energy it isusing is the amount it takes to use the accessories thatyou have on.

Save MoneyWhile there are many good environmental reasons toconvert, there are equally good economic reasons.First, if you already own the donor car, you don’t haveto pay for 70 percent of your “new” EV. Even if you haveto buy a car or truck to convert, it’s still cheaper. If youbuy a vehicle with a dead or tired engine, the costshould be lower than it would be if you were buying acar that you needed to get several years of reliableservice out of.

Even if you have to pay more for your donor carbecause the engine is in good shape, you can sell theengine and some of the other parts. Selling these partstakes some time and effort, but can put some moneyback into the EV project. Selling the leftover parts alsocontributes to the recycling benefit of converting.

Once you have converted the car, the real savingsbegin. Gone are the periodic oil changes and theexpensive tune-ups and maintenance services. Theinevitable muffler replacement has vanished along withthe rest of the exhaust system. Cooling system failures,which usually occur in the worst place at the mostinappropriate time, are a thing of the past. Theexpensive carburetor replacement, or the fuel injectionproblem that has the technician scratching his head andsaying things like “I’ve never seen a problem like thisbefore,” cease to exist when the fuel becomeselectricity.

The complexity of the new cars is putting their serviceand repair more and more into the hands of dealershipsinstead of independent repair shops. Even with longerwarranty periods and extended service intervals,servicing a car is getting more expensive.

The service and maintenance of a conversion EVrequires a specialist who is very familiar with the EV.The ideal service specialist is you—the person who didthe conversion. Since you wrote the documentation asyou did the conversion, you are the person bestqualified to repair and service your EV.

Don’t expect to put in too much time, though. Thesimplicity of an EV drive system and the reliability of thecomponents will limit your service tasks to checking thebatteries for water level and cleanliness, and keepingthe tires at the right pressure. The front brake pads orshoes should be checked frequently at first, until youget a feel for the effect of the additional battery weighton their wear rate.

The only other parts of the car that require attention arethe wheel bearings, drive axles, suspension parts likeball joints, and steering parts like tie rod ends. Theseparts are usually checked and replaced at the time theconversion is done, and have long service lives. Theirmaintenance and repair could be left to a professionalmechanic if you desire.

The service that is best left to a professional is wheelalignment. This is because of the need for veryspecialized and expensive equipment. Correct wheelalignment is a factor in the car’s rolling resistance,which influences range. Your new EV conversionshould have its alignment set as soon as it is finished.This will correct any errors introduced by thesuspension modifications made to compensate for theadditional weight involved in the conversion. Thealignment should be rechecked in about three months,after things have settled in during driving.

Save Time & WorrySome savings are not as tangible as drastically reducedmaintenance costs, or never again getting only coins


GoPower

back in change from a $20 bill after filling your gas tank.By the way, most EV drivers report not being able todetect an increase in their electric bill when they startdriving an EV on a regular basis. The amount ofelectricity the car uses is such a small fraction of theoverall household use—it disappears in normalfluctuations. This may change somewhat because ofrate hikes brought on by the so-called energy crisis.However, with gasoline prices also rising, operatingcosts will still be less for an EV.

An EV saves you time. You don’t have to take time tofind a gas station and fill the gas car’s tank. You don’thave to make an appointment to take the car in forservice as often. This involves arranging to be pickedup at the repair shop and taken back at the end of theday to get the car back.

An EV also lowers stress produced by wonderingwhether your faithful daily-driver and grocery-getter willpass its smog test, since EVs are exempt from testing.

Why Convert Instead of Buying New?We have shown that EVs help the environment, aid inenergy conservation, and have economic advantages.The question still remains, why convert? Why not justbuy an EV from a major manufacturer? They all havethem—you’ve seen them in all the magazines.

General Motors’ EV1 is the only one of the remainingfactory EVs available for lease to the general public, ata rate of from US$350 to US$500 per month dependingon battery type. Honda leased their EV+ to privatecitizens initially, but quit after leasing 300 of them. Theother manufacturers only lease their EVs to fleets.

This indicates reluctance on the part of the world’smajor automakers to put EVs into the hands of thegeneral public. In fact, John Wallace, the executivedirector of Ford’s TH!NK group, which oversees electricand alternative vehicles, said, “God doesn’t want us tohave full-function electric vehicles. The laws of naturedon’t allow this.” This kind of attitude is prevalent in therest of the auto industry.

There are two strategies the major manufacturers areusing to keep from producing a low-cost, practical EV.The first is the introduction of the high mileage, lowemission electrically assisted gas cars that they arecalling hybrids (see HP82 and HP83 for an explanationof these cars). The second EV avoidance strategy is thepromise of fuel cell cars.

Automakers are making a big show of their research onfuel cells to provide the electricity for EVs instead ofthose limited-range batteries. However, there is muchwork to be done before there is a fuel cell powered carin the average person’s driveway. In the meantime,

there is little research being done on batteries, and nofreeway-capable pure EVs are being built.

We have talked about the environmental and economicreasons to convert, and in doing so have come to thethird reason to convert a car to electric power. Thatreason is that doing a conversion is the only way anaverage person can get his hands on an affordable EV.

“How do I . . .?” Ask Me!This column turned out to be a long answer to a shortquestion, and it’s the same answer I gave to the manwho asked the question at the show. I don’t know yetwhat he will do with his car, but I hope I gave him somethings to think about. Please send me some moretechnical questions, and get me off the soapbox andback into the shop!

AccessMike Brown, Electro Automotive, PO Box 1113-HP,Felton, CA 95018 • 831-429-1989 • Fax: 831-429-1907 [email protected] • www.electroauto.com

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Communications

StarBand BroadBand Internet

ServiceTodd King ©2001 Todd King

Getting an internet connectionin an urban area is mostly adecision-making process.

You can choose from phone line internetproviders, digital subscriber links (DSL),T-lines, and cable-based systems. For arural homestead, the choices narrow,and until now, all but disappear for thevery remote home. But a new systemexists for anyone in North America,whether you live in town or not. It’scalled StarBand.The StarBand system is a high speed satellite Internetproduct that allows you to access the Internet from apersonal computer with no traditional modem or phoneconnection. This system allows up to 500 kilobits persecond (kbps) download and 150 kbps upload, directlythrough coaxial cable and a satellite dish. Dependingon the time of day, speeds may even exceed thesevalues. More users impact the server and slow it down,but I have never seen my system go below 400 kbps.

StarBand generally markets the download speed as tentimes faster than the fastest dial-up service. I have seenthe speed at fifty to sixty times faster than phone-based

connections. StarBand allows real-time audio, video,and data through a broad-band, high speed, two-wayInternet connection that’s always on and has no dial-up.There are no Internet providers involved other thanStarBand.

Product InfoThe system consists of a 24 by 36 inch (60 x 90 cm)satellite dish, usually mounted on a pole (2 inchschedule 40) at least 5 feet (1.5 m) above ground level.Two coaxial l ines, one for sending and one forreceiving, run from the dish to a satellite “modem.” (It’snot technically a modem, but that’s what StarBand callsit, since it has the same function.) The modem plugsinto a USB port on the back of your existing computer.Most computers manufactured within the last year willhave a USB port.

Computer RequirementsThis two-way Internet access system requires a fairlypowerful computer. But most people have a minimumsystem already, or could easily upgrade withaftermarket products readily available from a number of

COMM.POWERCOMM.POWER

The author’s StarBand dish—his first intstallation.


Communications

different suppliers. Basically, the minimum computercapabilities are:

• Pentium class CPU• 32 MB of RAM• 10 MB of free hard drive space• CD-ROM drive• USB port• Windows 98, Windows98se, Windows 2000, or

Windows Me. (Sorry MacHeads, the StarBandsystem is not yet Mac OS compatible. So far,networking Macs to the Windows StarBand machineis the only choice.)

If your existing computer meets these minimumrequirements, you can hook the StarBand systemdirectly to your USB port. If your system doesn’t have afree USB port, you will need to add a USB expansioncard or hub.

InstallationStarBand installation requires an authorized installer. Iwas one of the installers chosen for a six-month betatest of their prototype. It arrived in several boxes viaUPS ground. The manuals were very clear and easy toread. The process for installing was straightforward,with only a few terms that I did not understand withoutthe manual’s explanations.

The dish comes with wall mounting hardware. If it isinstalled on a pole, the pole must be 5 feet (1.5 m) high,with another 3 feet (0.9 m) in the ground in concrete.The hole should be about 8 to 12 inches (20 to 30 cm)in diameter. I used an 8 foot (2.4 m), 2 inch schedule 40pole that was purchased locally. I set the pole inconcrete and verified that the pole was plumb (vertical).This is extremely important! The satell ite isapproximately 22,000 miles (35,000 km) above earth,and one degree of misalignment on earth equals milesof error at the satellite.

I let the concrete cure for two days. While I waswaiting for the concrete, I assembled the satellite dishwith the enclosed instructions. The system comes withthe hardware and wrenches required for assembly.

I referred to the charts provided to establish theelevation, skew and azimuth angles for my latitude andlongitude. I set the elevation and skew before I put thedish on the pole. Elevation is the angle up and down.Skew has to do with the angle needed when the dish isrotated. The azimuth is the angle side to side. When theconcrete had cured, I set the dish on the pole and slid itall the way down to the seat, a tab that keeps the dishcollar from sliding too far down.

I ran two RG-6 coaxial cables from the satellite modemto the dish, and crimped on standard coaxial

StarBand—A User’sTestimonial

Richard Perez ©2001 Richard Perez

The Way It WasOver the last fourteen years, we have had sevendifferent radiotelephone systems spanning the 6 mile (10 km) distance between our editorial office and thenearest telephone line. We’ve never been able to getany modem to move faster than 7,200 bits per second(bps) on a radiotelephone system. Most of the time, ourmodem speed varied between 2,400 bps and 4,800bps. The scene during deadlines was ugly—sixstressed-out nerds fighting over a single slow dataconnection.

The Way It IsWe now have a blazing fast Internet connection, withdownload speeds averaging around 500 kbps andupload speeds about half that. This is over one hundredtimes faster than our fastest radiotelephone connection,and about ten times faster than a modem-based hardline telephone connection.

And best of all, we have had up to eight computersusing the single StarBand “modem” at the same time,with no noticeable slowdowns. No more fighting overthe data communications line—everyone can do emailand surf the Web at the same time. The speed increasehas made telecommuting blossom for us. No longer do Ihave to let my computer run all night just to download a4 MB file from one of Home Power’s advertisers orauthors. Now that file arrives in a matter of a fewminutes at most.

Computer DetailsWe are a Macintosh office. StarBand is currentlyavailable only for PCs running Windows. We solved thisproblem by installing a PC and making it both anInternet proxy server for the StarBand system, and a fileserver for all the Macs. My rationale for using this PC asa file server is that since it’s a PC, no one in this officewill want to use it as a stand-alone computer—we aremostly Mac jockeys.

The PC is connected to the StarBand SB180 “modem.”We use WinProxy software as an Internet proxy serverand it services both PCs and Macs. We use PCMacLansoftware to emulate AppleTalk, which enables our Macsto use the hard drives on the PC just as if they wereMac drives on a network.

All the various computers communicate via anEthernet local area network (LAN). Most of themachines are operating at 100 base T speeds. Thismeans we can move about 1 MB per second over ourLAN. So all the Macs are talking to the PC proxyserver at high speeds, and they all have very fastInternet connections via the StarBand system. Prettyslick, and it works great!


Communications

connectors at each end. I applied heat shrink tubing tothe crimped connections to make sure theseconnections stay watertight. I ran a #6 (13 mm2) bare,solid copper ground wire from the dish framework, theLNB (low noise block converter), and the coaxialground block to a dedicated 8 foot (2.4 m) ground rod.

With the elevation and skew already set, all I had to dowas find the azimuth. Most installers will use aspectrum analyzer to arrive at the best azimuth for yourarea. This is an expensive meter that measures thestrength of the signal received by a satellite dish. But Ilive in a remote little town, and the closest spectrumanalyzer was about 100 miles (160 km) away.Fortunately, there is a computer-based signal strengthmeter provided to StarBand installers. It is used to setthe dish at the best azimuth.

With the signal strength meter on my computer screen,I approximated the degrees azimuth out at the dish andjust kept turning it back and forth until I got the highestreading. For my installation, I was able to get a signalstrength of 83 percent. I did hit 84 percent once, butwas never able to get it back again.

A signal strength of 70 percent or better is needed forreception. Most installers achieve reception strengthsomewhere between 75 and 85 percent. There are toomany factors involved to get 100 percent—dust, clouds,solar flares, trees, buildings, pollution, etc. After I’dtuned to the best signal I could get without a spectrumanalyzer, I tightened all the nuts and bolts to keep thedish from moving.

The system was wired! Now the software had to beloaded onto the computer, and a few parametersneeded to be set manually. This went fairly easily with acall to StarBand’s toll-free technical support number.They ran me through the setup, and helped me plug inthe right parameters for my zip code. After about a halfan hour on the phone, I was surfing!

For new installations today, there is no on-screen signalstrength meter. I have to call and set up the bandwidthbefore I get to the site. After installation and roughantenna alignment on site, I call an automated systemto check the co- and cross-polarization figures. Co-polarization is the signal strength and cross-polarizationis the noise involved in any broadcast signal. They area ratio and must meet FCC criteria in order for theStarBand system to be activated.

Performance & Power RequirementsThe system is extremely fast. Live stream video andaudio require no downloading—it’s instant and clear,with great reception and no static on the audio. Surfingis enjoyable, with Web sites loading faster than I haveever seen.

A friend with a Digital Subscriber Link (DSL) at hishome in the San Francisco Bay area recently visitedme. He couldn’t believe the speed of StarBand.Remember, StarBand is a digital satellite unit—not alink to a phone-based system somewhere else. It is notshared with anyone; it’s always on and has no dial-up.

I ran the prototype unit on a Trace 2012SB modifiedsquare-wave inverter for an off-grid test, and had notrouble whatsoever. I hooked all the power supplies forthe system to a watt-hour meter to see if the systemwould easily kill a small battery bank. Here are the results:

• With CPU, ink jet printer, 15 inch (38 cm) monitor,speakers, and modem turned on, startup drew 130 to135 watts.

• With CPU, ink jet printer, 15 inch monitor, speakers,and modem turned on, it drew 120 to 122 watts.

• With CPU, ink jet printer, 15 inch monitor, speakers,and modem turned on, surfing drew 125 to 140 watts.

• With only the CPU and speakers on, the system drew72 watts.

• With everything plugged in, but not running, there wasa phantom load of 2 to 8 watts.

System CostAssuming that you will use your current computer, thesystem costs will be determined by what you want toreceive in programming. The satellite system costsUS$400, including modem, dish, wall mount, andsoftware. You own the equipment. Installation will runUS$200 local—more for travel. Unlimited Internetaccess only is US$70 per month. Unlimited Internet,150 channels of digital TV, and 30 channels of constantmusic, through Dish Network is US$100 per month.

Please note that you can be on the Internet and watchTV at the same time. There is some additional cost toDish Network for parts and installation of thecomponents needed to access digital TV. Dish Networkreceivers start at US$100.

Internet Off-Grid!Never before has there been such a product for theprivate homeowner. All other satellite Internet systemsthus far can only download from the net and must use aphone line to upload. This is of little help to the remotehome. These systems needed to tie up the cell phoneat exorbitant rates, or operate through a radio phone atthe normal slow rate of data transfer.

The StarBand system can be used anywhere in NorthAmerica. Trees, hills, snow, etc. will affect reception.The satellite footprint can be viewed on the StarBand’sWeb site. The “modem” is a significant phantom load,so you have to turn it off when it’s not in use.Sometimes the system will need to go through a short“wake-up” period after being turned off.

The very reliable StarBand components have beenused for many years in other countries and forcommercial purposes. The FCC has made thistechnology available to the common consumer now,and it is sure to be used extensively by urban and ruraldwellers alike. The benefit to the off-grid home isinvaluable.

Until now, Internet access was the last greattechnological hurdle of off-grid living. If a person wantsto live remotely and communicate with their “.com,” orwants Internet access on a reliable basis for any otherreason, the StarBand system is just the ticket.

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Word Power

Parallel—Side by SideIan Woofenden ©2001 Ian Woofenden

Derivation: From Greek para, beside, and allelon, ofone another.

Series circuits are single loops, with all circuitcomponents in a row, and no branches. The electronsin series circuits are like a simple toy train setup. All thecars in the train are connected, and whatever happensto one car happens to them all.

Some of the electrons in the circuit will flow througheach bulb, and they will both light up. The two bulbs areoperating independently, energized by one source. Ifone bulb fails, the other will still run. In contrast, if twobulbs are wired in series (all in one loop), when onefails, the circuit is opened and the other bulb will go out.

Just as multiple roads allow a greater traffic flow,parallel circuits allow greater electron flow (compared toa single series circuit with the same wire size). You areincreasing the amount of conductor material, so moreelectrons can flow.

Parallel circuits also make using electrical energy muchmore flexible and convenient. You can wire multiplecircuits and control them independently. Wiring andcircuit components only need to be sized for the specificloads on each circuit. In the same way, having multipleroads allows our bicycle commuters to travel to avariety of places by different routes.

Renewable energy systems are full of parallel circuits.Most PV arrays are made up of series strings ofmodules that are paralleled together in a combiner box.Voltage remains the same when you wire in parallel,while amperage is the sum of the output of the sources.So if two 12 volt (nominal) PV modules that produce 5amps are wired in parallel, the output will be 10 amps at12 volts.

Batteries can also be wired in parallel. If you have two12 volt batteries to use in a 12 volt system, they will bewired in parallel. Again, voltage will remain the same,while amp-hour capacity will increase. If each of yourbatteries is rated at 200 amp-hours at 12 volts, twowired in parallel will supply 400 amp-hours at 12 volts.

Conventional house wiring systems are made up ofparallel circuits—it’s the normal wiring mode for mostelectrical systems. The main energy supply can be theutility grid or a renewable energy system. The energycomes into a main circuit panel, where the wiringdivides into multiple circuits. Each circuit leads to agroup of loads, which are also wired in parallel withinthe circuit.

Parallel and series circuits are wired together in variousways to make up electronic devices and wiringsystems. All circuits are either series, parallel, or somecombination of the two. Series circuits are in a singleloop. Parallel circuits are, as the original Greek says,“beside one another.”

AccessIan Woofenden, PO Box 1001, Anacortes, WA 98221Fax: 360-293-7034 • [email protected]

Renewable Energy Terms

Series Circuit

Parallel Circuit

Electrons in parallel circuits are like multiple trainstraveling on more than one track. Or you could imaginebicycle commuters leaving the suburbs and heading fortheir jobs downtown. They can take many differentroutes to reach similar destinations.

In the simplest parallel electrical circuit, there will be asource of energy (battery, PV, or utility grid) and twoloads. As an example, let’s use a battery and two lightbulbs.


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Power Politics

BANKRUPT!Michael Welch ©2001 Michael Welch

O n April 6, 2001, Pacific Gas &Electric Company (PG&E), oneof the world’s largest investor-

owned utilities, declared bankruptcyunder Chapter 11 of the U.S.Bankruptcy Code. “How could thispossibly happen?”, queried themultitudes.I’m in PG&E territory, and so is Redwood Alliance, thenon-profit environmental group I’ve been active with foryears. Since 1978, Redwood Alliance has been fightingPG&E for fewer nukes and more renewables. With thiskind of history, you might ask how I could remainunbiased enough to write about this subject.

But look at it the other way. The reason we have had tofight PG&E is that they constantly inflict their corporategreed and hostility on their ratepayers, who are captivecustomers. Pacific Greed & Extortion is a commontake-off on their name. This bankruptcy does nothing tochange that reputation.

Over the years, Redwood Alliance’s successes dealingwith PG&E on a local level have come easier. The localPG&E plant manager now calls us to respectfullydiscuss our position whenever something new comesup. They’ve figured out that we are strong in ourcommunity, and that what we have been asking for isthe right thing to do. (Of course, it also helps that ourideas have proven to be the least costly for thecompany.)

But on a state-wide level, our group is insignificant toPG&E—we are unable to be a big league player.Believe me, we’ve tried. But no group is able to play onthe same level as PG&E. They have the big bucks tothrow at anything they want to influence. And they alsohave long-term investments in the legislature and the

Public Utilities Commission. This clout, by the way,enabled them to get almost everything they wanted inCalifornia’s “deregulation” debacle.

Corporate Spin-OffPart of what they got was the spinning off of the localuti l i ty, separating it f inancially from the parentcorporation. Well, it wasn’t really a separation. It wasmore like a one-way street for cash assets. This spin-offallows profits to flow from the utility to the parentcompany, while at the same time insulating the parentfrom the utility’s problems if something goes wrong.

There is one major reason for such a spin-off—thepotential for debt relief by declaring bankruptcy. PG&Eknew very well that if the cost of doing business inCalifornia got high enough, they would not be able tocollect enough money from the ratepayers to pay theirbills. So they needed to protect all their profits fromattack by future debts.

Nuclear Power a CulpritNuke power caused deregulation, and the California“crisis” was the result. Diablo Canyon Nuclear PowerPlant was forced into the rate base by PG&E clout insuch a way that nearly all of PG&E customers’ electricitybills increased by 50 percent. Manufacturers and otherbusinesses hollered loudly, wanting whatever it wouldtake to bring prices down. Their goal became figuring outa way to decrease their prices with true deregulation,allowing power suppliers to compete for their business.

But things did not work out very well. Once again,PG&E’s clout allowed them to influence deregulationlegislation. They influenced the legislation so that itwould pay them vast amounts of ratepayer money fortheir past investments in “stranded assets.” These arepower plants they were allowed to build that wouldtheoretically no longer be cost-effective underderegulation. The price tag for those stranded assets?Nearly US$30 billion, US$20 billion of which gotlaundered off to PG&E’s parent company. (At the timeof bankruptcy, PG&E’s debt was about US$9 billion.)

At the same time, PG&E was forced to sell off itsconventional power supply assets to California’s newenergy suppliers. I say forced, but actually it was PG&Ethat influenced the deregulation law. How can acompany force itself to do something it doesn’t want todo? The profits from the sales of those plants also wentup the hill to the parent corporation.

In the meantime, PG&E, under its favorablederegulation scheme, was having to pay higher andhigher wholesale rates for the electricity that it wasselling to its customers. Even though California hadbeen “deregulated,” the only way the legislation wouldpass was if there were rate rollbacks and a freeze built

PowerPolitics


Power Politics

into the law. So PG&E could not raise retail rates, whileits wholesale electricity costs were increasingdramatically. In this way, the local utility startedamassing debts. And of course, it was not at allinterested in tapping into the money it had laundered offto the parent company.

But why should they care? Their profits were wellinsulated by the parent company. And besides, theparent company also owned natural gas and electricproduction facilities, and was in the process of chargingits wholesale customers the same outrageously highrates that the local utility was now complaining about.

The utility feared all alongthat they might have todeclare bankruptcy. Infact, their board hadgiven management theleeway to do so nearlyfour months before thedeclaration. So whatfinally threw them overthe edge? It was California’s governor, Gray Davis. Hehad come up with a protection scheme to keepCalifornia’s utilities solvent. He knew he couldn’t passdebts up to the parent company, and he also feared thathaving bankrupt utilities could cripple the Californiaeconomy. He came up with plans to funnel lots of statemoney to the utilities to bolster their finances until suchtime as the deregulation laws could be fixed.

Trade Grid for BailoutBut Davis wanted something in return for giving thisbailout money to the utilities. He was moving forward ona proposal to trade the bailout for state ownership of theutilities’ transmission lines. PG&E balked at this idea, andI don’t blame them. How the heck could a utility continuein business without anything to do business with?

Deregulation had forced them to sell off most of theirproduction assets. With the exception of their nukeplant, hydro facilities, and a handful of other assets,the only thing they had for moneymaking was sellingpower access. This requires ownership of thetransmission lines.

So, in spite of Herculean efforts to get cash to theutilities, PG&E figured out how to have their cake andeat it too. Under federal bankruptcy laws, a company isallowed to continue doing business while the dispositionof company assets is placed in a court’s hands. Whichdebts are paid and how much is paid are left to thecourt as well.

While the utility may yet lose its transmission lines tothe state or other creditors, this is going to be one of

those courtroom battles that will take years to play out.All sides will have their bevies of attorneys. They will fileone motion after another, mostly delaying finality.

This is the largest investor-owned utility ever to declarebankruptcy, and the third largest bankruptcy in history.The assets of the utility that will be distributed tocreditors are mostly future utility bills. So one questionis, can the bankruptcy judge increase rates in order topay off debts? And that leads to a second question:what interest should take priority—the consumer or thecreditor? And then there is yet another player, the state,which has been funneling funds into the utility to keep it

solvent. Where do they fitinto the lineup for dividingup ratepayer money?Yikes, it ’s enough tomake my head spin!

Other ShenanigansPG&E is primarilyconcerned with its owninterests. Just before

declaring bankruptcy, which has the effect of freezingassets, PG&E distributed about US$50 million inbonuses to its managers. Governor Davis concludedthat, “Management at PG&E is just focused on paddingtheir own pockets, not in discharging their duty to servetheir many customers in California.”

Other victims of PG&E greed include the independentcompanies that were selling green power in California.For customers that had PG&E as their electricityprovider, billing was as it had always been. But thosewho were purchasing power from companies like GreenMountain had two bills. One was from the provider, andthe other was from the utility, for transmission costs andother costs related to deregulation.

But because of the mandated rate rollbacks and freezementioned above, the billing was very convoluted. Theenergy providers passed their increasing costs on totheir customers, which led to higher bill amounts thanPG&E customers had. The mandated rollbacks andfreeze were dealt with via a credit showing up on theconsumers’ PG&E transmission bills.

The problem was that PG&E would not pay out thosecredits, but just let them build up. In the meantime, folkswere having to pay the fully increased rates via theirproviders without the relief of refunds from PG&E.Eventually, Green Mountain and other providers turnedover all their customers to the local utilities. It was thebest thing they could do for the customers, to avoidsending us all to the poorhouse. In this way, PG&Eforced their competitors out of business in the amountof time it took electric rates to climb in California.

PG&EBANKRUPT


Power Politics

Too Complex for MeThis is a very complex situation that Ihave tried to describe in a fewhundred words. Books will be writtenon this subject in the next few years.Classes will be taught. Lawyers willmake mill ions. In fact, PG&Ebankruptcy attorneys had alreadybeen paid US$1.5 million by April 9,three days after the filing.

But you should be left with a singleperception. It is corporate greed thatfueled this entire debacle, from thefirst plans for the Diablo Canyonnuke plant, to the eventual dividingup of the leftover assets of aCalifornia utility that was gutted byits own parent.

AccessMichael Welch, c/o RedwoodAlliance, PO Box 293, Arcata, CA95518 • [email protected]/redwood

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Don Loweburg ©2001 Don Loweburg

Fuel Cells—A Red Herring?

Fuel cells using hydrogen representa non-polluting energy conversiontechnology. Yet many articles in

the popular press miss the mark in amajor way by referring to fuel cells asalternative or renewable energy. Fuelcells are not a source of energy inthemselves.Fuel cells are a conversion technology, transforming thestored chemical energy in hydrogen and oxygen toelectrical energy. In a true hydrogen fuel cell, thisprocess is accomplished without pollution. However thefuel (hydrogen) must come from somewhere. In orderfor this process to be renewable, the hydrogen mustcome from a renewable source. This is possible, butmost fuel cells today do not use renewably producedhydrogen. Rather, these cells are designed to usenatural gas, or in mobile applications, gasoline.

Fuels cells that operate on hydrocarbon fuels have anextra step using a “reformer.” This process strips thehydrogen away from the carbon backbone of thehydrocarbon molecule, leaving CO2 as a byproduct. Insome cases, the fuel cells operate on biogas(methane). In these instances, it would be correct torefer to the system as renewable.

In most articles in the popular press, the fuel cells beingdiscussed are operating on non-renewable hydrocarbon

fuel. Yet the word fuel cell is often allowed to implyrenewable. I consider this to be a dangerous trend.Consciously or unconsciously, the authors allow thisdistinction to be fuzzed over.

Of course hydrocarbon fuel cells have merit. Theyconvert energy contained in the fuel with higherefficiency than an internal combustion engine. However,these fuel cells represent only an incremental efficiencyimprovement. In no way are they renewable orrevolutionary. And, since they are fueled withhydrocarbons, they will emit CO2, and they aregreenhouse gas polluters! I think the vigorous mediaattention paid to fuel cells is a red herring, distractingthe public from truly renewable energy sources like PVand wind.

Though PV and wind systems in operation faroutnumber fuel cell installations by several orders ofmagnitude, you wouldn’t know it from the pressexposure. Though a hydrocarbon fuel cell may free youfrom the electric monopoly, you must purchase gasfrom a hydrocarbon monopoly. This is notindependence.

Also keep in mind that residential-sized fuel cells arenot yet for sale, and the price of natural gas (thepreferred fuel) is going up steeply. These issueschallenge the view that the hydrocarbon fuel cell will bea bridge technology, easing the transition from a non-renewable to a renewable energy economy. Perhapswe can jump the gap and do away with the bridge!

Good NewsDuring the last several issues, I have reported onprograms and legislation related to photovoltaics inCalifornia. Among them was the ICE-T proposal (theelimination of all standby charges on PV systems up to1 MW) before the California Public Utilities Commission(CPUC), net metering for large systems, and a proposalbefore the California Energy Commission (CEC) toincrease the rebate for renewables.

PV has scored a home run in California, thanks to somevery hard work by members of the PV industry,CALSEIA’s legislative advocate Kathryn Lynch (whohas a PV system on her own home), and someprogressive legislators.

On April 11, 2001 Governor Davis signed AB29,extending net metering to systems up to 1 MW, andremoving capacity restrictions, previously capped at 0.1percent of system capacity. There is one caveat. Due tostrong behind-the-scenes lobbying by PG&E, the 1 MWnet metering legislation was amended at the last minuteto sunset in two years. The PV industry plans to makeevery effort to extend the law.



The PV industry got another big boost on May 16,2001, when the CEC increased the EmergingRenewables Buydown Program amount to US$4.50 perwatt or 50 percent of system cost. While 60 percent ofthe funding is reserved for small systems under 10 KW,40 percent is available for systems of all sizes.

Bad NewsAt the same time as these positive changes, electricrates in California have gone up significantly. Notsurprisingly, the U.S. demand for PV systems has nowreached record levels. This increased demand, coupledwith already high demand in Europe and Asia, hasresulted in significant backorder and delays.Bottlenecks are particularly acute in the availability ofsome inverters and PV modules. Many modulesuppliers are about two months backordered.

Xantrex (Trace) has had particular problems deliveringtheir ST2500 line tie inverter. Numerous andcontradictory reasons have been presented, rangingfrom software problems to production and engineeringproblems. At the time of this writing, one majordistributor is backordered by two hundred units. Thismeans that two hundred customers and dealers arewaiting to complete their system installation, and this isjust one distributor’s backorders.

To make matters even more aggravating, Xantrex hasannounced a July 1 release of an upgraded ST referredto as the XR. A Xantrex spokesperson explained thatthe XR had a number of production improvements anda new “Power Sweep” maximum power point trackingdesign. It also has a price increase of US$259! Thoughthe spokesperson did his best to put a positive spin onthis situation, my conclusion is that Xantrex could notmeet market demand at the original price, and neededto re-engineer their troublesome maximum power pointtracking software.

Fortunately, Xantrex is not the only product on themarket. Other manufacturers such as Omnion and AESseem to be doing a better job of fulfilling their customercommitments. Also, a new player is in the U.S. market,SMA, manufactures the Sunny Boy line of inverters.Their 2.5 KW inverter has just received UL listing andCEC certification. John Berdner, SMA America, reportsthat units are now being shipped to distributors from themanufacturer in Germany.

Though most module manufacturers forecast adoubling of production this year, we can anticipatesupply problems for some time. More than ever, it isimportant to work with established and knowledgeabledealers.

California Buydown ConcernsConcerns about system quality and an anticipated rushon the California market prompted a recent (May 22,2001) PV Summit meeting in Sacramento, California.Hosted by the CEC and moderated by Bill Brooks(Endecon Engineering), attendees included modulemanufacturers, CEC staff, IPP, CALSEIA, and SMUD.

Two primary concerns surfaced during the roundtablediscussion. On the part of the CEC, it was that thegenerous rebate coupled with supply bottlenecks wouldincrease system prices, a result diametrically opposedto the goals of the CEC buydown program. The othermajor concern, expressed by Bill Brooks, was that inCalifornia, we could have a replay of the solar hot waterdebacle of the 1980s. (I don’t agree with thisconclusion, but that’s not the point here.)

Though module manufacturers assured the CEC thatsupplies could be maintained, they made no commenton prices. There were no inverter manufacturerspresent. As already noted, Xantrex has increased theprice on the ST2500 by 10 percent.

IPP pointed out that installers generally are competitiveon hardware and labor, but cannot control the pricesthey are charged by manufacturer-distributors (maybewe should look at this!). The CEC representative madeit very clear that they would be looking at system-pricingbehavior over time, and that they had the power toadjust the rebate level at any time.

Regarding the schlock factor, a couple of points weremade. Chuck Whitaker (Endecon Engineering) pointedout that unlike solar thermal collectors, no one would bebuilding PV equipment in their garages. In fact allcomponents used in the CEC program must beapproved, and as a minimum requirement, modulesand inverters must be UL approved. This factrepresents a big difference between the PV industry oftoday and the solar thermal industry of the early 1980s.Bill Brooks countered by saying that even the bestequipment could be installed incorrectly, componentsmismatched, wire sizing goofed, and PV modules sitedpoorly.

The group had consensus in three main areas. First,the CEC should maintain a program of randomsampling of system quality and performance. Generalproblems or egregious offenders would be identified.

Second, many customers may not know how well theirsystems operate. A simple remedy, benefiting bothcustomer and installer, would be to include systemoutput metering. Many dealers already include this, andno one objected to this being a program requirement.



The third item of consensus was that training andcertif ication standards should be developed forinstallers and designers. It was noted that efforts in thisarea are already well underway in some sectors of thePV industry. The group decided to explore the workalready developed, and possibly implement a programrequirement over the next few years.

Module Energy OutputSandia National Laboratories does research andsupport activities related to photovoltaic componentsand systems. I recently received an issue of theirQuarterly Highlights titled “Modeling Annual EnergyProduction From Photovoltaic Modules.” The articledetails research and work done by David King andothers using modeling software developed by his groupat Sandia. This and many other important reports areavailable from Sandia’s Web site. A commercialimplementation of the software is available fromwww.mauisolarsoftware.com (reviewed in IPP, HP79).

PV installers and many Home Power readers are awareof the basic routine for estimating PV module output. Asouth-facing orientation with a tilt angle equal to thelocation’s latitude is assumed as a standard. King’sarticle takes on the more complicated, real world issuesof estimating module output, and quantifies the results.It answers questions like: What is the effect ofhorizontal or vertical placement of the module? Whatare the differences in performance between differentcell technologies? How important is diffuse light toperformance? How do different modules perform indifferent climates?

To answer these questions, the author first establishesa methodology to normalize the different modulestested, using output at standard test conditions. In orderto level the playing field, the module’s annual energyoutput was used. By focusing on annual energy output,many small, seasonal effects were averaged out. Thismakes sense, since the annual energy output is whatshould be the measure of merit, not the various andsometimes confusing terms like Isc, Vpp, etc.

King makes one very important conclusion. Thestandard reporting condition (SRC), also called thestandard test conditions (STC), can be a good basis toevaluate module performance. Modules with equalpower ratings were found to produce equivalent annualenergy output within a 10 percent variance across arange of geographic locations. However, since SRCratings form the basis of the “nameplate” rating for agiven module, any errors in this rating will translate intoerrors in annual energy output.

Mr. King states, “As a result, consumers must insist thatmanufacturers provide accurate nameplate ratings for

their product, ideally with the nameplate valuerepresenting a production average, with some modulesslightly above that value and some slightly below.” Hemakes this point because he is well aware that somemanufacturers cherry-pick the modules.

For example: A 100 watt module may typically have a10 percent specification for output variation. Amanufacturer could (and some do) select all 90 wattmodules and sell them with the 100 watt rating,asserting that they are within the 10 percentspecification. One would expect a “normal” distributionof module output around any rated output value.Because so much rides on the SRC rating, there’s areal case for independent module testing, somethingalong the lines of a Consumer Reports for modules.

A final and most important point is made in the Sandiaarticle. Since equally rated modules (equal SRC output)differ by at most 10 percent in annual energy output, wemust look at system issues that can affect output bymuch larger amounts. The article concludes, “Reliabilityof power conditioning equipment is the single mostimportant concern related to system-level annualenergy production and user satisfaction. TheDepartment of Energy program needs to continue toemphasize research in this critical area.”

System Energy OutputQuantifying system performance is the next big step forthe PV industry. There is a deep need here for anindependent entity to perform this function. Again, aConsumer Reports of the PV industry could fulfill thisfunction. Consumers must now deal with performanceclaims based on the disparate perspectives of thevarious component manufacturers. Modulemanufacturers emphasize features like “cell efficiency,”“low light performance,” and “shade tolerance,” whileinverter manufacturers promote “peak efficiency” and“clean output.”

These aspects of component performance areimportant, but the primary question should be, “Howmuch energy does a system produce per year?” Ofcourse, experienced installer-designers do have abetter handle on this question because they haveempirical results based on their specific geographicalarea.

However, it’s time the industry became accountable forsystem performance. Naive, overly optimistic estimatesneed to be replaced with knowledgeable data. We havegood system modeling software available. When it isused in conjunction with good empirical field data,reasonably accurate predictions of system performanceare possible.



The View From OffshorePV Power is the newsletter of the International EnergyAgency (IEA). This group provides very good globalinformation on the PV industry. The newsletter and alarge number of reports are available at its Web site. Iwon’t drag you through all the numbers, but this is someof the best information (and very nicely presented) that Ihave found. It’s free, and comparable in quality to thestuff that is sold in some of the U.S. “PV insider” rags.Those darn European socialists!

Jade Mountain CorrectionIn IPP, HP82, I discussed the Gaiam purchase of RealGoods, and mentioned that Gaiam also owned JadeMountain. I got a message from Steve Troy correctingthat statement. The fact is that Steve owns 51 percentof Jade Mountain, while Gaiam owns the other 49percent.

Steve also took strong issue with my use of the term“consciousness widget” as a description of the futuredirection of Real Goods and Jade Mountain. He sentme a copy of Jade’s catalog to support his point. Thecatalog indeed maintains a strong focus on renewableenergy equipment and systems. I apologize for theslight to Jade Mountain, and to Real Goods too.

AccessDon Loweburg, IPP, PO Box 231, North Fork, CA 93643 559-877-7080 • Fax: 559-877-2980 [email protected] • www.i2p.org

Sandy Miller, Emerging Renewables Buydown,California Energy Commission (CEC), 1516 9th St, MS 45, Sacramento, CA 95814 • 916-653-2834Fax: 916-653-2543 • [email protected]/greengrid/index.html • BuydownInformation: 800-555-7794, or for weekly fundingupdate call 800-900-3594

California Public Utilities Commission (CPUC), 505 VanNess Ave., San Francisco, CA 94102 • 415-703-2782Fax: 415-703-1758 • [email protected]

David L. King, Sandia National Laboratories,Photovoltaic System R&D, Dept. 6218 MS0752, PO Box 5800, Albuquerque, NM 87185 • 505-844-8220Fax: 505-284-3239 • [email protected]/pv

International Energy Agency (IEA), Mrs. HesterPruiksma, Utrecht University, Utrecht Centre for EnergyResearch, Padualaan 14, 3584 CH Utrecht, TheNetherlands • +31 30-2537641 • Fax: +31 [email protected] • www.iea-pvps.org

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Code Corner

OvercurrentDevicesJohn Wiles

Sponsored by the Photovoltaic Systems Assistance Center, Sandia National Laboratories

In the Code Corner columns inHP76–83, I addressed the selectionand sizing of conductors for

renewable energy systems. How do weprotect these conductors from long-duration overcurrents that might causefires or shocks if allowed to continue?Overcurrent devices provide therequired protection, and this CodeCorner will be the first of severaladdressing these devices.We have sized the conductors in our system to operatewithin the rated temperature of the wire insulation atsome maximum current. If that current is exceeded forsignificant periods of time (depending on the magnitudeof the overcurrent), the conductors and the insulationwill be heated. As the conductor temperature passesthe rated temperature of the insulation (60, 75, or 90°C;140, 167, or 194°F), the properties of the insulation willchange. The hotter the insulation gets above the ratedtemperature, the faster the insulation characteristicschange, and the more they change.

Some insulation (thermoplastics like THHN) may soften,melt, and then smoke before catching fire. Others(thermoset plastics like RHW) may start to char andbecome brittle before catching fire. Operation above therated temperature for any significant length of time willchange the insulation properties that make the wiresafe, and will reduce its life. These changes in theinsulation may not be perceptible, but they may behazardous.

Types of OvercurrentsOvercurrents can be grouped into categories. Startingsurge currents from motors or electronic devices at twoto ten times normal running current can last 1 to 8seconds. Overloads are in the range of two to six timesnormal rated circuit current and can last from minutes tohours. Fault currents are unexpected and unwantedcurrents, at varying levels, that can occur on the normal

circuit conductors or on grounded conductors. They canbe continuous (low levels) to very short-lived (highlevels) in a well designed system.

Overloads are the result, as the name implies, ofconnecting too many loads to a given circuit, orconnecting loads that draw more current than the circuitis rated to deliver. Most electrical circuits are designedto be operated at only 80 percent of their rating. Whileoperating above this level may not cause theovercurrent device to trip, it may result in long-termdegradation of the circuit wiring and overcurrentdevices.

Overcurrents from faults can result from mechanicalfailures of insulation, failures of connections, or abusesof the wiring such as nail punctures, saw cuts, orgeneral wear and tear. Fault currents are called line-to-line faults if the fault or short circuit involves both of thecurrent-carrying conductors. If the fault involves a circuitconductor and a grounded conductor, an equipment-grounding conductor, or a grounded surface, the fault issaid to be a ground fault.

Fault currents may be in the milliamp range whenleakage currents or high-resistance faults are involved.Very high fault currents, up to the ability of the powersource (which may be thousands to tens of thousandsof amps) may occur when a direct, low-resistance,unwanted connection is made.

Overcurrent DevicesThe main types of overcurrent protection devices usedin renewable energy systems are fuses and circuitbreakers. These devices have been around for over100 years and have been steadily refined in that time.These devices are very sophisticated in their internalconstruction. They use electrical, mechanical, magnetic,thermal, and chemical processes to achieve the desiredcharacteristics.

The characteristics that are required in an overcurrentdevice are stringent and difficult to achieve. Not allovercurrent devices meet all of the criteria for allapplications. This is why there is a large selection ofovercurrent devices, with a wide range of appearancesand costs.

In general, all overcurrent devices are designed to opena circuit when subjected to overcurrent, and thenreduce that current to zero. These devices have aspecific opening current rating, also known as theampere rating. They must also have a voltage ratingand an interrupt current rating.

The voltage rating specifies the maximum voltage thatthe device can be subjected to, including device-to-ground voltage and the voltage across the device after


Code Corner

it has opened the circuit. The interrupt current rating isthe amount of short-circuit current that the device caninterrupt (reduce to zero) when opening. All overcurrentdevices must be able to function properly and safelywhen subjected to any voltage up to the rated voltageand any current up to the interrupt current rating.

Strangely enough, short-circuit currents and voltagesbelow the maximum values are far harder to handlethan those near the maximums. High short-circuitcurrents tend to cause internal fuse elements to meltrapidly and completely, creating a long open circuit paththat the current must jump. Lower short-circuit currentsdo not melt the fuse elements as completely, whichleaves smaller gaps in the internal element. Thecurrents jump across these smaller gaps more easilythan the longer gaps, and the internal fuse mechanismshave more trouble extinguishing the arcs.

Circuit breakers have slightly different problems relatedto the strength of the magnetic fields that cause theirinternal contacts to open. Lower short-circuit currentscause the contacts to open more slowly, and the arc isharder to extinguish than when higher short-circuitcurrents force the contacts to open rapidly.

Each device, fuse, or circuit breaker is designed for itsspecific application. “Slow-blow” fuses or time-delaycircuit breakers are designed to not respond to currentsurges, but only to longer duration overloads. “Fast-blow” fuses and short-delay circuit breakers aredesigned to respond very quickly to overcurrents abovetheir rating, and may even open if subjected to normalstarting surges from motors and electronic devices.

Both slow- and fast-acting overcurrent devices may beused for overcurrent protection in code-compliantsystems. The specific application will determine whichdevice should be used. In another category are“semiconductor” fuses, which are designed to respondextremely quickly to protect semiconductors insideelectronic equipment. Unfortunately, this characteristiccannot be achieved while meeting the code and ULrequirements to respond properly to overloads in thetwo to six times rating area. So these fuses are notapproved for use in code-compliant systems.

AC & DC Are Not the SameIt is not safe to use an overcurrent device listed only forAC in a DC application. AC currents go to zero andreverse themselves 120 times per second (on 60 Hzsystems). Any arc formed when an overcurrent deviceopens is extinguished and restruck 120 times persecond. This greatly assists the overcurrent device ininterrupting the current and forcing it to zero. DC currentdoes not provide this self-extinguishing effect, and sinceit flows in one direction only, the overcurrent device

must bear the complete load of breaking the circuit andextinguishing the arc.

The difficulty in interrupting DC currents is quite evidentin the ratings of the common 100 amp type RK-5, DC-rated fuse. This fuse is listed for use on both AC andDC systems. The ampere rating is 100 amps AC andDC. The AC voltage rating is 250 volts. The DC voltagerating is only 125 volts. The fuse can interrupt AC short-circuit currents up to 200,000 amps. The DC interruptrating is only 20,000 amps. Half the voltage and one-tenth the interrupt rating highlight some of the difficultiesassociated with DC circuit overcurrent protection.

FusesFuses act once in protecting a circuit from overcurrents,and then they must be replaced. Special fuse holdersmust be used to allow safe replacement of the blownfuse. These protect the user from coming into contactwith energized circuits. In many cases, the fuse holderis incorporated into a disconnect switch that removesvoltage from the fuse when opened.

Listed fuses are available in two categories. “Class”type fuses are subject to more rigorous testing in termsof the interrupt rating, the number of cycles at full load,environmental conditions, mechanical design, and otherfactors.

“Supplementary” fuses, on the other hand, aredesigned to be used in circuits where the conditions ofuse are much less severe. They are usually protectedfrom high short-circuit currents by class type fuses—hence the name supplementary; they supplement otherovercurrent protective devices in the system.

Class type fuses are more robust, and can be used inall applications. When used in DC circuits, the fusemust also be listed for DC use. The RK-5 fusementioned above is a class type of fuse. Other fusesthat may have DC ratings are class RK-1, CC, J, T, andL. These fuses are available with various ampereratings, voltage ratings, and interrupt ratings. Class typefuses may have standard ampere ratings of 1, 3, 6, 10,15, 20, 25, 30, 35, 40, 45, 60, 70, 80, 90, 100, 110, 125,150, 175, 200, 225, 250, 300, 350, 400, 450, 500, andhigher, up to 6,000 amps.

“Supplementary” type fuses can be used only in DC PVsource and output circuits. This type of fuse includesthe midget fuse and one or two ceramic fuses in the 1/4by 1-1/4 inch (6 mm x 32 mm) size. These fuses havelimited interrupt capabilities (500 to 1,000 amps or so),and are allowed only in the PV source circuits that aresome distance from the sources of high, short-circuitcurrents like the battery. Ratings are usually in one-ampincrements from one to 30 amps.


Code Corner

Very few of these fuses are listed for DC. Care must beused when selecting these fuses or replacements toensure that the replacement has a DC rating and listing.Fuses available at electronics hobby stores may looksimilar, but usually do not have the listing or DC ratings.Where possible, it is suggested that the more robustclass type of fuse be used in all applications. Due tovolume production, the class fuses are, in some cases,cheaper than the supplementary fuses.

Circuit BreakersCircuit breakers can be reset after opening, and can bereset numerous times. They can also be used asdisconnect switches. Replacement is not needed afterevery operation. Only the operating handle is exposed,and the energized contacts are not accessible to thesystem user during normal operation. Circuit breakersare known as inverse-time devices, and they havevarious time delay curves, just as slow-blow fuses do.

For example, a circuit breaker rated at 30 amps mustcarry 30 amps continually without tripping. It must openwithin one hour when carrying 135 percent of 30 amps(40.5 amps), and it must open in 2 minutes whensubjected to 60 amps (200 percent of rating). Withinthese ranges, the circuit breaker may be designed forslow or fast response to short-term (1 to 2 seconds) andlong-term (2 to 8 second) surges.

Circuit breakers are also available in two versions. The“branch-circuit-rated” circuit breaker is equivalent to the“class” type of fuse. There are also supplementary ratedcircuit breakers that could be used in PV source andoutput circuits, but these are not commonly available. Inall cases, DC-rated and listed circuit breakers should beused in DC circuits.

Time ConstantsWhen a short circuit occurs, the fault current does notrise instantaneously to the maximum value determinedby the source voltage and the circuit resistance. Thereis a time constant involved that is determined by theresistance, inductance, and capacitance of the circuit.These in turn are controlled by the insulation type,conductor spacing, and length of each circuit.

Fuses and circuit breakers for DC systems are testedand listed to operate with time constants of 10milliseconds or less. This time constant impactsovercurrent device performance in two ways. First wehave the useful current-limiting fuses, and second wehave the problems associated with time constants thatare too long.

Current-Limiting FusesA normal fuse (non-current-limiting) will sense the short-circuit current as the current increases past the fuseampere rating on the time-constant slope toward the

maximum value. These standard fuses will eventuallyopen the circuit and extinguish the arc, provided thatthe maximum available short-circuit current is lowerthan the interrupting capability of the device. However,the current through the circuit may reach or nearlyreach the maximum available short-circuit current forthe circuit. These high levels of current may damageother components in the circuit.

Current-limiting fuses will also sense the rising currentas it passes the ampere rating of the fuse. They will,however, act much faster than the non-current-limitingfuse to open the circuit and extinguish the arc. Theaction is so fast (substantially less than 10 milliseconds)that the current never has a chance to increase to theshort-circuit maximum current. The short-circuit currentis held to a much lower value that results inconsiderably less stress to circuit components. Current-limiting fuses are sometimes required on battery circuitswhere the available short-circuit currents can be veryhigh. There are no current-limiting circuit breakers listedfor use on DC systems.

Long Time ConstantsDC overcurrent devices may not work properly if thecircuit time constant is substantially longer than 10milliseconds. The overcurrent device may have troubleextinguishing the arc. At voltages below the maximumrated voltages and at low short-circuit maximumcurrents, long time constants prove especiallytroublesome.

As the length of the circuit conductors increases, theresistance of the circuit increases. As the spacingbetween parallel circuit conductors (positive andnegative) increases, the inductance of the circuitincreases. Capacitance varies with spacing, but not in auniform manner. These three factors (resistance—R, inohms; inductance—L, in henries; and capacitance—C,in farads) serve to determine the time constant of thesystem.

The NEC requires that all conductors in a circuit,including the equipment-grounding conductor, be routedtogether and remain in close proximity. In DC circuits,this action keeps the time constant as low as possible.In AC circuits, impedance is minimized.

PV system designers and installers should keep thisrequirement in mind when working on module andbattery wiring. All of the conductors for each circuitshould be grouped together in the same conduit orsheathed cable to keep the time constants low.

Overcurrent Devices for Other SystemsYes, there are many overcurrent devices (both fusesand breakers) that are used on other DC systems suchas electronic, appliance, telecom, automotive, boat, and


Code Corner

mining systems. Most of these overcurrent deviceshave not been evaluated by the listing organizationsagainst the UL standards and NEC requirements offixed electrical power systems.

For example, automotive fuses and circuit breakers aredesigned (at very low cost) to be used in relatively high-resistance circuits (one conductor is the steel autobody; or small wires are used) that limit the availableshort-circuit currents to a low value. They do not havesufficient interrupting capability to deal with the muchhigher short-circuit currents found in fixed-powersystems. When used in fixed-power systems, such asPV systems, they may create hazardous conditionswhen they are required to function.

Very expensive, high-reliability, overcurrent devicesmade for industrial and telecom systems may meet thetechnical requirements for use in a PV system. But theyhave not been evaluated or listed for use in RE systemsthat must meet NEC requirements.

Generally, the overcurrent devices available and listedfor use on fixed electrical power systems are the lowestcost means of achieving the required protection. To useovercurrent devices that are not listed, or that areintended for other industries, may either sacrifice safetyor increase cost.

SummaryUngrounded conductors in all circuits are required tohave overcurrent protection. The proper fuse or circuitbreaker can provide this protection. DC ratings arerequired for overcurrent devices used in DC circuits.Keeping all of the conductors of a particular circuit inclose proximity will keep the time constant low andallow the overcurrent devices to function properly. Infuture Code Corner columns, I will address whereovercurrent devices should be used, and how to sizeand select the proper devices.

Photovoltaic Power Systems and the NationalElectrical Code: Suggested PracticesThis 117 page manual, written by the Code Cornercolumn author, and published by Sandia NationalLaboratories, has been revised to the 1999 NEC, and isavailable in PDF form on our Web site:www.nmsu.edu/~tdi/pvandnec.htm

This manual is also available from Sandia NationalLaboratories by calling Connie Brooks at 505-844-4383or e-mailing her at [email protected].

Questions or Comments?If you have questions about the NEC or theimplementation of PV systems that follow therequirements of the NEC, feel free to call, fax, e-mail, orwrite me. Sandia National Laboratories sponsors my

activities in this area as a support function to the PVindustry. This work was supported by the United StatesDepartment of Energy under Contract DE-FC04-00AL66794. Sandia is a multi-program laboratoryoperated by Sandia Corporation, a Lockheed MartinCompany, for the United States Department of Energy.

AccessJohn C. Wiles, Southwest Technology DevelopmentInstitute, New Mexico State University, Box 30,001/MSC 3 SOLAR, Las Cruces, NM 88003 • 505-646-6105 Fax: 505-646-3841 • [email protected]/~tdi

Sponsor: Sandia National Laboratories, Ward Bower,Department 6218, MS 0753, Albuquerque, NM 87185505-844-5206 • Fax: [email protected] • www.sandia.gov/pv

National Electrical Code® and NEC® are registeredtrademarks of the National Fire Protection Association.The 1999 NEC and the NEC Handbook are availablefrom the NFPA, 11 Tracy Dr., Avon, MA 02322800-344-3555 or 508-895-8300 • Fax: 800-593-6372 or508-895-8301 • [email protected] • www.nfpa.org

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Home & Heart

Kathleen Jarschke-Schultze©2001 Kathleen Jarschke-Schultze

We had a power blackout at ourhouse the other morning!When we woke up, our power

was off. Unlike grid blackouts, this onewas caused by too much power. Ourcreek was still running our microhydrounit, the sun was shining on our panelsthe day before, and the wind crankedour turbine all night long.When our batteries are full, the excess electricity goesby shunt regulation to a heating element in our waterheater tank. That had maxed out, so our system turneditself off—the inverter shut down due to high voltage.Bob-O turned it back on, and I had a day of doinglaundry, vacuuming, and running air cleaners with theTV on in the background for company. When thebatteries are full, the only way we can waste power is tonot use it.

Mousie Wars lllEver since I moved to the country from town sixteenyears ago, I have had a hate/hate relationship withmice. Brown or gray, it just doesn’t matter. I have hadseveral rodent adventures. I refer you to Muddy Roadsin HP12 and HP21. Just to spark your curiosity, the firststory involves a snake in my oven, and the second, agun in my kitchen.

I always had cats as pets and mousers before I metBob-O, so mice were never a problem. Bob-O,however, is an asthmatic. Cats are the catalyst for him. Igave my best mouser, Maxine, to my friend Joan when Imoved into Bob-O’s cabin. We must avoid any contactwith cats. This means all my clothes must immediatelygo into the wash after visiting my cat-keeping family.We can’t stay with friends who have cats. I have gottenvery good at bringing our own sleeping environment ontrips.

House MouseWhenever we noticed indications of mice, we would seta trap line. We used the old fashioned Victor snap trap,

about ten at a time. It would take up to a week ofchecking and emptying them all every morning tomanage the problem. Peanut butter is good bait, and soare cotton balls soaked with bacon grease. Contrary tothe cartoons we grew up with, cheese only works so-so.

My food pantry is down in our basement. When I firststarted using it, I could see where the mice had chewedholes in the ceiling and corners for unrestricted entry. Imixed cayenne pepper and powdered mustard withmortar, and filled all the holes. This kept them fromusing those routes, but they eventually made newentrances elsewhere in the room.

My old office was in our basement. I worked down therein the summer when the coolness was a relief. In thewinter, I would move my computer upstairs, closer tothe wood stove. As soon as I was not a daily presence,the mice would move in.

The Rat BastardsA friend got me a little miniature Zen rock garden in asmall wooden tray. After artfully placing the rocks, Imake lines in the sand with a tiny rake to representflowing water. I even have a tiny porcelain fishermanwho sits on the edge and fishes in the garden. Anotherporcelain couple picnic on the opposite side.

After I moved out of the basement office, every time Ireturned, there were mouse tracks all through my Zengarden. Like bullies at the beach, the mice would knockover my little porcelain people and kick sand in theirfaces. By checking my little garden, I knew whether ornot I had to set the trap line in the office.

Mouse-No-MoreThen Bob-O brought home some Vermin-X® electronicindoor pest repellers. Huh? That’s what I thought. Theyare little white boxes that plug directly into an outlet, likea night light. They repel mice, spiders, cockroaches,fleas, and most flying and crawling insects. That’s whatthe label says. Since mice were my only problem, thatwas all I cared about.

They work! Yippee, skippy! I can tell you, I’m thrilled.First we put them in the basement—one in the pantryand one in my office. Every time I would check, therewas no mouse sign or scat. My little Zen gardenremained raked and pristine. My porcelain people wereunscathed by rodentia.

Bob-O went out and got more. He found them atPrice/Costco in a four pack for US$29.95. They can befound at many home supply stores. We placed the unitsin the kitchen, guest room, and greenhouse. We havenot seen a mouse or any indication of one (in thehouse, that is) in months.

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Pests are repelled because they can’t adapt to theVariable Frequency Technology™. The units can beused to drive household pests from homes, garages,attics, crawlspaces, or basements. They’ll workanywhere you have an outlet. They are notweatherproof though, so if you use them outside, bringthem in during wet weather. I have to be careful not toget the ones in my greenhouse wet when I water inthere.

They are safe for use around pets, fish, infants, andsmall children. The product literature does warn not touse them around pet mice, hamsters, gerbils, etc. Theunits plug directly into any standard 110 VAC electricaloutlet. Some models have a night light; mine do not.

There is a small red LED light on the front to tell youthat the unit is on. I plugged mine into a Brand meter(model 4-1850 DR), and the draw was so small that itdidn’t even register. Our power system can afford suchsmall phantom loads. Note: This unit is a tiny load, butthat also means it will not bring the inverter out ofsearch. And it becomes a large load (combined with theinverter) when it’s the only load.

Technical SpecificationsFor Model #100/1000, the unit dimensions are 4-3/4 x2-3/4 x 2-1/8 inches (12 x 7 x 5.4 cm). The deviceweighs 4 ounces (113 g). Coverage is 1,000 square feet(93 m2), and the frequency range is 26,000 to 42,000Hz. Power input is 110 or 220 VAC, and powerconsumption is 0.090 W. This UL-listed device has atwo year limited warranty with refund or replacement.

I Hate Mieces to PiecesWill I miss the thrill of the chase? Will I miss finding asheet in the linen cupboard with holes chewed into thefolded edge, so that there are holes every 12 incheswhen the sheet is unfolded? Absolutely not. Millions ofpeople love Mickey Mouse. If you are about my age,you got your first taste of opera from Mighty Mouse.Speedy Gonzales was amusing, way back when. Butwhat I look forward to now are nights where nothing isstirring, not even a mouse.

AccessKathleen Jarschke-Schultze is busy as her bees in heryard and garden in Northernmost California, c/o HomePower magazine, PO Box 520, Ashland, OR [email protected]

Weitech, Inc., PO Box 1659, 601 N. Larch St., Sisters,OR 97759 • 800-343-2659 or 541-549-0205Fax: 541-549-8154 • [email protected] • Vermin-X pest repellers

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Happenings

INTERNATIONALFree instructions, photos, drawings, & specs tobuild solar cookers & water systems with localmaterials purchased with local currency.Sunstove, www.sungravity.com

Green Empowerment finances microhydro & other RE projects in Nicaragua, thePhilippines, & Borneo. Volunteers needed.www.greenempowerment.org

Solar On-Line Internet courses. Year-round. PVTechnology & Opportunities; PV SystemsDesign Basics; PV Systems Design:Professional; Solar Homes: Healthy Buildings;Solar Energy for Global Development. SóL, PO Box 217, Carbondale, CO 81623 Fax: 559-751-2001 • [email protected]

CANADAAlberta Sustainable House; open house 3rd & 4th Saturdays, 1–4 pm. Cold-climate features& products for health, environment,conservation, RE, recycling, low energy, self-sufficiency, appropriate technology, autonomous& sustainable housing. Free. 9211 Scurfield Dr.NW, Calgary, AB T3L 1V9 Canada403-239-1882 • Fax: [email protected] • www.ucalgary.ca/~jdo

The Institute for Bioregional Studiesdemonstrates & teaches ecologically oriented,scientific, social, & technological achievements.IBS, 393 University Ave., Charlottetown, PEI C1A 4N4 Canada • 902-892-9578

Vancouver Electric Vehicle Association. Call formeeting info. PO Box 3456, 349 West Georgia,Vancouver, BC V6B 3Y4 Canada604-878-9500 • [email protected]

INDONESIANov. 7–10, ‘01; RE Indonesia, Jakarta. Part ofElectric Indonesia trade show. OverseasExhibition Services, 11 Manchester Sq., London,U.K. W1M 5AB • +44 (0)20 78622090/2000Fax: +44 (0)20 78622098/[email protected] • www.montnet.com

JAPANNov. 11–16, ‘01; Enviro Shiga 2001. NagahamaDome, Shiga, Japan. Int’l. environmentalbusiness exhibition, incl. RE, waterconservation, waste reuse & recycling,environmental monitoring, & environmentallysound products. Shiga Env. Business ExhibitionAssoc., Shiga Pref. Gove Bldg. 4-1-1, Kyomachi,Otsu City, Shiga, 520-8577, Japan+81-77-528-3793 • Fax: +81-77-528-4876www.pref.shiga.jp/event/messe

NICARAGUAJan. ‘02, Nicaragua. Intro to PV for developingcountries, course offers lectures, fieldexperience, & eco-tourism. Taught in English byDr. Richard Komp & Professor Susan Kinne.US$850. Contact Barbara Atkinson 215-942-0184 • [email protected]

SPAINOct. 29-31; First International Conference onSolar-Electric Concentrators, Marabella, Spain.Technical discussions of achievements inconcentrating solar electricity, primary emphasison PV. Contact: Robert McConnell, NREL 617Cole Blvd. Golden, CO 80401 • 303-384-6419Fax: 303-384-6481 • [email protected] www.nrel.gov/icsec

TURKEYAug. 29–31, ’01. 2nd International SarigermeSolar Electricity Workshop, Iberotel SarigermePark, Ortaca, Turkey. Contact: Tanay Sidki Uyar,+90 252 2868031 • Fax: +90 252 2868043 [email protected]

NATIONAL U.S.Pollution Prevention Video Series. Appalachia—Science in the Public Interest offers 42 videos,incl. Solar Dry Composting Toilets, Solar HotWater Systems, PV, Solar Space Heating, Solar-Powered Automobiles, Quilted Insulated WindowShades, & more. US$25 + S&H, broadcast-quality tapes available. ASPI Publications, 50 Lair St., Mt. Vernon, KY 40456606-256-0077 • Fax: • [email protected] • www.kih.net/aspi

American Wind Energy Association. Info aboutU.S. wind industry, membership, small turbineuse, & more • www.awea.org

State financial & regulatory incentives for RE:reports. North Carolina Solar Center, Box 7401NCSU, Raleigh, NC 27695 • 919-515-3480Fax: 919-515-5778www.ncsc.ncsu.edu/dsire.htm

Energy Efficiency & Renewable EnergyClearinghouse (EREC): Insulation Basics(FS142), New Earth-Sheltered Houses (FS120),PV: Basic Design Principles & Components(FS231), Cooling Your Home Naturally (FS186),Automatic & Programmable Thermostats(FS215), & Small Wind Energy Systems for theHomeowner (FS135). EREC, PO Box 3048,Merrifield, VA 22116 • 800-363-3732TTY: 800-273-2957 • [email protected]

Energy Efficiency & Renewable Energy Network(EREN): links to gov. & private internet sites & “Ask an Energy Expert” online questions tospecialists. 800-363-3732 • www.eren.doe.gov

Green Power Web site: deregulation, greenelectricity, technology, marketing, standards,environmental claims, & national & statepolicies. Global Environmental Options & CREST • www.green-power.com

National Wind Technology Center. Assisting windturbine designers & manufacturers withdevelopment & fine tuning. Golden, CO303-384-6900 • Fax: 303-384-6901

Sandia’s Stand-Alone Photovoltaic SystemsWeb site: design practices, PV safety, technicalbriefs, battery & inverter testingwww.sandia.gov/pv

Solar Energy & Systems. Fundamentals ofSmall RE: Internet college course. Weeklyassignments reviewing texts, videos, WWWpages, & email Q&A. Mojave CommunityCollege • 800-678-3992lizcaw@et.mohave.cc.az.uswww.solarnmc.mohave.cc.az.us

Federal Trade Commission (free pamphlets):Buying An Energy-Smart Appliance, EnergyGuide to Major Home Appliances, & EnergyGuide to Home Heating & Cooling. EnergyGuide, FTC, Rm 130, 6th St. & PennsylvaniaAve. NW, Washington, DC 20580202-326-2222 • TTY: 202-326-2502www.ftc.gov

Solar Curriculum for schools. Six week sciencecurriculum or individual sessions—free! Over 30classroom presentations & demos using free orlow-cost materials. Susan Schleith, Florida SolarEnergy Center • 321-638-1017www.fsec.ucf.edu

ALABAMACentre, AL. The Self-Reliance Institute of NEAlabama seeks people interested in RE, earth-sheltered construction, & other self-relianttopics. SINA, 6585 Co. Rd. 22, Centre, AL35960

ARIZONASep. 14-16, ‘01; SW RE EXPO. Prescott Valley,AZ. Info: Prescott Valley Economic DevelopmentFoundation • 888-240-4256 • www.pvfdf.com

Glendale & Scottsdale, AZ. Living with the Sun:Lecture series by AZ Solar Energy Assoc.History & current overview of concepts, design,applications, & technologies on solarheating/cooling, architecture, landscaping, PV, & cooking. 7–9 pm, 1st Wed. of month atGlendale Foothills Branch Library, & 3d Tues. ofmonth at Scottsdale Redevelopment & UrbanDesign Studio. Jim Miller • 480-592-5416

Tax credits for solar in AZ. ARI SEIA602-258-3422

ARKANSASSun Life Constr. by Design: Seminars 3rd Sun.of month. Hands-on, incl. ferro-cement, buildingdwellings for minimal materials expense. LorenImpson, 71 Holistic Hollow, Mt. Ida, AR 71957870-867-4777 • [email protected]

CALIFORNIAOct. 20, ’01; Solar Cooking Summit, AguaCaliente Park, San Diego County, CA. BoilingWater Recipe Contest, share info & technicalinnovations, solar oven building classes. Forevent questions or rule list, contact Ian Zalewski,[email protected]

Sept. 22–24, ‘01; Take Your Bedroom Off theGrid; Arcata, CA. Hands-on workshop: How toinstall PV as your budget allows. Workshop withJohnny Weiss. Redwood Alliance, PO Box 293,Arcata, CA 95518 • [email protected]/redwood

Arcata, CA. Campus Center for AppropriateTechnology, Humboldt State University. Ongoingworkshops & presentations on alternative,renewable, & sustainable living. CCAT, HSU,Arcata, CA 95521 • 707-826-3551


Happenings

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Rebates for PV & wind. CA EmergingRenewables Buydown Program, CA EnergyComm., 800-555-7794 or [email protected]/greengrid

Dec. 11-14, ‘01; Sacramento, CA. EVAA ElectricTransportation Industry Conference. BatteryEVs, hybrids, path to commercialization. 650-365-2667 • www.evaa.org

Energy Efficiency Building Standards for CA. CA Energy Comm. 800-772-3300www.energy.ca.gov/title24

Sep. 30-Oct. 5, ‘01; UPEx’01: PhotovoltaicExperience Conference & Exhibition. HyattRegency, Sacramento, CA. PV & distributedgeneration. Solar Electric Power Assoc. Contact:Julia Judd, 1800 M Street, NW, #300,Washington, DC 20036 • 202-857-0898Fax: 202-223-5537 • [email protected]

COLORADOCarbondale, CO. SEI: hands-on workshops. 1-2 week sessions. PV Design & Installation,Advanced PV, Wind Power, Microhydro, SolarCooking, Environmental Building Technologies,Solar Home Design, & Straw Bale Construction.Solar Energy International (SEI), PO Box 715,Carbondale, CO 81623 • 970-963-8855Fax: 970-963-8866 • [email protected]

FLORIDASep. 17-21, ‘01; Biomass Conference of theAmericas. Orlando Rosen Centre Hotel.Bioenergy & bio-based products, technologies,markets, & policies. Info: 321-638-1527www.nrel.gov/bioam

IOWASept. 8–9, ‘01. 10th Annual IRENEW EnergyExpo. Hiawatha, IA at Prairiewoods. Electrathoncars, straw bale constr., wind, solar heat, PV, & energy conservation workshops. Iowa REAssoc., 319-875-8772 • [email protected]

July 1–Sept. 31, ‘01; Iowa Electrathon season.Reg. US$44 incl. fees for all events, insurance,rule book, manual, & newsletter subscription.Iowa Electrathon, Nora Johnson, CEEE, Univ. of Northern Iowa, Cedar Falls, IA 50614319-273-7575 • [email protected]

Prairiewoods & Cedar Rapids, IA. Iowa REAssoc. meets 2nd Sat. every month at 9 AM. Allwelcome. Call for schedule changes. IRENEW,PO Box 355, Muscatine, IA 52761319-288-2552 • [email protected]

KANSASOct. 22-27, ‘01; Matfield Green, KS. Women’sWind Power workshop. Wind system design,components, site analysis, system sizing, and ahands-on installation of a full-size wind turbineand tower. US$550. Solar Energy International.See “COLORADO” for SEI access.

KENTUCKYLivingston, KY. Appalachia—Science in thePublic Interest. Projects & demos in gardening,solar, sustainable forestry, more. ASPI, Rt. 5,

Box 423, Livingston, KY 40445 • Phone/Fax:606-453-2105 • [email protected] • www.kih.net/aspi

MASSACHUSETTSGreenfield Energy Park needs help preservingthe historic past, using today’s energy & ideas,creating a sustainable future. Greenfield EnergyPark, NESEA, 50 Miles St., Greenfield, MA01301 • 413-774-6051 • Fax: [email protected] • www.nesea.org

MICHIGANTillers International, classes in draft animalpower, small farming, blacksmithing, & woodworking. 5239 S 24th St., Kalamazoo, MI 49002 • 616-344-3233 • Fax: [email protected] • www.wmich.edu/tillers

MINNESOTA‘01 MREA Workshops. See “WISCONSIN”

MONTANAAug. 20–25, ‘01; Biodiesel workshop, Max Farm,Superior, MT. Incl. biodiesel & straight vegetableoil. See “COLORADO” for SEI access. LocalCoordinator: David Max • [email protected]

Whitehall, MT. Sage Mountain Center: one-dayseminars & workshops, inexpensive sustainablehome building, straw bale constr., log furniture,cordwood constr., PV, more. SMC, 79 SageMountain Trail, Whitehall, MT 59759Phone/Fax: [email protected]

NEW HAMPSHIRESpinning a Web of Solar Spirits; workshops onliving with the sun. 1st Wed. every month.Sunweaver, 1049 1st, NH Turnpike, NH 03261603-942-5863 • Fax: [email protected]

NEW MEXICOOct. 4-6, ‘01; Photovoltaic System Installationcourse, Albuquerque. A hands-on, how-tocourse. Supplement distance learning withpractical hands-on skills. Solar-on-Line. See“International” for access info.

NORTH CAROLINASep. 24-29, ‘01; Asheville, NC. PV Design andInstallation workshop. Site analysis, systemsizing, component specification, appliances, labexercises, and a hands-on system installation.US$550. Solar Energy International. See“COLORADO” for SEI access

Saxapahaw, NC. How to Get Your Solar-Powered Home: Seminars 1st Sat. each month.Solar Village Institute, PO Box 14, Saxapahaw,NC 27340 • 336-376-9530Fax: 336-376-1809 • [email protected]

NEW YORKTax credits. Info on grid connection & tax credits:NY State PSC,www.dps.state.ny.us/photovoltaic.com

Loan fund. Info on low interest financing for RE:NY Energy $mart Program, NY State Energy R & D Authority • 518-862-1090 ext. 3315Fax: 518-862-1091 • [email protected]

OHIOPerrysville, OH. RE classes: 2nd Sat. eachmonth. Straw bale class 3rd Saturday, throughSept. Solar Creations, 2189 SR 511 S.,

Perrysville, OH 44864 • 419-368-4252www.bright.net/~solarcre

OREGONAug. 9, ‘01; Ashland, OR. Energy workshop, 7-10 pm, 51 Winburn Way. Home energyefficiency, solar power, cut and manage energyuse. With Christopher Dymond, Geoff Dawson,& Bob-O Schultze. Free. No contact info, justshow up.

Aug. 10–20, ‘01. Williams, OR. Adv.Permaculture Design Certificate Course—Keyline Water Management: A Whole SystemsApproach. Become more competent designers.Cost: US$1,100. Seven Seeds Farm, 3220 E.Fork Rd., Williams, OR 97544 • [email protected]

Sept. 14-15, ‘01; Roseburg, OR. AlternativeEnergy Fair, Umpqua Community College. Fairon 15th, kickoff dinner the 14th. Lectures,booths, & exhibits in hydrogen, solar, wind,hydro, biomass, and hybrid vehicles. Info:Bonnie Kyle, [email protected]

Cottage Grove, OR. Adv. Studies in AppropriateTech., 8 wks., 4 interns per quarter. AprovechoResearch Center, 80574 Haxelton Rd., CottageGrove, OR 97424 • [email protected] • www.efn.org/~apro

Sept. 8, ‘01; Seneca, OR. Oregon Tree Farmersof the Year. Sustainable forestry & sustainableliving tour at Lance & Jennifer Barker’s MorningHill Forest Farm. EORenew, PO Box 485,Canyon City, OR 97820 • [email protected] • www.solwest.org

Nov. 3, ‘01; EORenew Annual Meeting. JohnDay, OR. Elections, program, summary of theyear’s events. See above for EORenew access.

RHODE ISLANDEnergy Co-op is being organized to provide RE,energy efficiency & conservation services, & group purchases of “Energy Star” products.Erich Stephens, • [email protected]

TENNESSEESummertown, TN. Kids to the Country: naturestudy program for at-risk urban TN children.Sponsors & volunteers welcome. The Farm,Summertown, TN 38483 • 931-964-4391Fax: 931-964-4394 • [email protected]

TEXASSept. 28–30, ‘01; Texas RE Roundup,Fredericksburg. Exhibits, demonstrations,workshops, tours. Texas RE Industries Assoc. & Texas Solar Energy Society, PO Box 9507,Austin, TX 78766 • 512-345-5446Fax: 512-345-6831 • [email protected]

El Paso Solar Energy Association bilingual Website. Info in Spanish on energy & energy saving.www.epsea.org

El Paso Solar Energy Association: meetingsnormally held 1st Thur. each month. EPSEA, POBox 26384, El Paso, TX 79926 • [email protected] • www.epsea.org

Houston Renewable Energy Group: meets lastSun. of odd months at TSU EngineeringBuilding, 2 PM. HREG, PO Box 580469,


Happenings

Houston, TX 77258 • [email protected]/hreg/HREGhome.htm

WASHINGTON STATEOct. 11–14, ‘01; Guemes Island, WA:Microhydro workshop. Class & labs followed bytours, incl. Canyon Industries, turbinemanufacturer. US$400. See “COLORADO” forSEI access • Local coordinator: Ian Woofenden,PO Box 1001, Anacortes, WA 98821360-293-7448 • Fax: [email protected]

Oct.15–20, ‘01; Guemes Island, WA: PV Design& Installation workshop, with Windy Dankoff.Site analysis, system sizing, equipment,appliances, demonstrations, lab exercises, & a complete hands-on installation. US$550.See “COLORADO” for SEI access. See abovefor local coordinator.

Oct. 22–27, ‘01; Guemes Island, WA: Build YourOwn Wind Generator workshop, with HughPiggott of Scoraig Wind Electric, Scotland.US$550. See “COLORADO” for SEI access.See above for local coordinator.

WISCONSINSep. 8, Basic PV, St. Paul, MN. Sep. 9,Intermediate PV, St. Paul, MN. Sep. 16-22, WindSystems Install, Blue Mound, WI. Sep. 21-23 & 28-30, Straw Bale, Browntown, WI. Oct. 6,Basic PV, Custer, WI. Oct. 7, Intermediate PV,Custer, WI. Nov. 10, Masonry Heaters Intro,Custer, WI. Nov. 26-30, RE for the DevelopingWorld, Custer, WI. Call for cost, instructors, & more info. Significant others half price. MREA,7558 Deer Rd., Custer, WI 54423715-592-6595 • Fax: [email protected] • www.the-mrea.org

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Wizard Speaks

FleetingGlimpses

Here’s a look into the idea well that constitutes the mindof the wizard. I hope you find it interesting.

• Chaos, or complexity, theory could possibly provide abasis for creating a unified field theory.

• A space-time that is curved implies that some form ofenergy is stored in the curvature.

• The Heisenberg Uncertainty Principle is both atheoretical and an observational problem, yet it maynot be a reality problem.

• A unified field theory may be derivable from a singlemulti-valued, multi-variable scaler function.

• It may be that the operating system of the humanbrain is based on the principles of chaos theory.

• What happens to the charge when a particle and itsanti-particle annihilate each other?

• Some gamma-ray bursts may be caused by theexplosion of black holes.

• Although low probability states are infrequent, they areaccessible.

• Is mass related to or a partial function of intrinsic spin?

• Perhaps the quantum wave function never reallycollapses.

the Wizard

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Adopt a Library!When Karen and I were living with kerosene lamps, we went to our localpublic library to find out if there was a better way to light up our nights.We found nothing about small scale renewable energy.

One of the first things we did when we started publishing this magazinethirteen years ago was to give a subscription to our local public library.

You may want to do the same for your local public library.We’ll split thecost (50/50) of the sub with you if you do.You pay $11.25 and HomePower will pay the rest. If your public library is outside of the USA, thenwe’ll split the sub to your location so call for rates.

Please check with your public library before sending them a sub. Somerural libraries may not have space, so check with your librarian beforeadopting your local public library. Sorry, but libraries which restrict accessare not eligible for this Adopt a Library deal—the library must give freepublic access. — Richard PerezTo Adopt a Library write or call

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Letters

ErrataThere is an error in HP83,page 33. The schematic of WillGreenslate’s system mistakenly has one ofthe PV array’s positive bus bars grounded in thecombiner box, creating a short circuit. The negativebus bar on the left side of the box should have beenshown as grounded instead, as this system is actuallywired. We apologize for this error.

Civic IrresponsibilityDear Mr. Perez, Hello from western Michigan! We havea story unfolding that you may want to take a look at.It’s a tragedy in the making, and has nationalimplications.

We live in Kentwood, Michigan, a city just southeast ofGrand Rapids. We live in a rural area (cows, chickens,windmills, goats, etc....). We feel strongly that weshould do our part of solving the energy crisis loomingin front of our country, And we don’t want to see ourenergy bills climb any higher. So our family decided tomake the move to solar energy. We began an odysseyof research, trying to decide what renewable energysystem would work best for our area of the country.

Prior to purchasing anything, we called the city ofKentwood Zoning Board office to get the rules andregulations regarding the installation of a solar energysystem. The woman we spoke with told us that the cityhad nothing on the books regarding the installation ofsolar energy systems, and that we could proceed. Sowe did.

We bought a state-of-the-art solar-electric system. Itconsists of twenty solar-electric panels on a tracker—the panels move with the sun. It starts off facing east inthe morning, tracks south as the sun rises in the sky,and ends the day facing the sun in the west. A solararray such as this nets an average of 40 percent moreenergy than a fixed array that you typically see onsomeone’s house or garage roof. The total cost was inexcess of US$25,000. So far, we have been able to beoff the utility grid (Consumer’s Energy) nearly 100percent of the time.

About one week after the installation of this fabuloussystem, we received a letter from the city stating thatwe were in violation of the city height restrictionordinance, and that two neighbors were complainingabout it because they said it was ugly.

To make a long, awful story short, we took it to theZoning Board of Appeals and lost—miserably. Theboard’s decision was made before we even stood up totalk. They said that these types of systems have noplace in Kentwood, that they are ugly (Yes, boardmembers were actually expressing their personalfeelings about the system’s appearance!), and that itdiminished Kentwood in general!

This board meeting was a sham. To begin with, only fiveof the seven board members even showed up. Onewas away at an “outing” and didn’t bother to show upuntil 9:00 PM, despite the fact that the meetingconvened at 7:30 PM. They simply didn’t know wherethe other two board members were—they just “didn’tshow.” Unprofessionalism at its very best! Themembers who were there flatly refused to look at thescientific reasoning for positioning the tracker where itneeded to be. They said shadows from trees locatedeast and west of the tracker had nothing to do thefunction of the solar panels, an opinion which couldn’tbe more incorrect. We had all kinds of charts andinformation there that substantiated the necessity forthe tracker position, but they would not even listen.They also refused to consider the merits of the systemitself.

Two days after the meeting, our local newspaper ran anAP story about the city of Chicago embracing greentechnology, both wind power and solar power. They, asa city government, are acknowledging the absolutenecessity for all of us to open our minds to alternativeways to power our lives. What a shame that Kentwoodis moving in the opposite direction.

We’re writing to you because this is an important storyfor all of us. Our president is encouraging all of us tomake conservation measures, and is even offeringincentive programs for people like us to put inalternative energy systems. We need localgovernments to get out of the way, in the name ofprogress and energy conservation, and allow people tomake their own power!

We’re the first in Kentwood to ask for this variance inthe height ordinance for a solar-electric system. Theyflatly refused us. I’m sure there are others in the countrygoing through this same battle. We have a majorcontradiction between what our federal government isasking us to do and what our local governments areallowing us to do. It’s only going to be through major

Ashland, OR 97520

Home Power LettersP.O. Box 520

Pow R. MakerSunnyville, Earth


Letters

national discussion and exposure that we are going toput these closed-minded zoning board members in theuncomfortable position of having to conclude that theyneed to wake up and join us in the 21st century.

Power in the future simply must included renewableenergy systems. Ours is the latest and greatest, cutting-edge technology. It’s powerful, it’s efficient, and it’spowering our entire home—lights, heating, cooling,appliances, TV, computers—everything. It’sunconscionable that a city government in this day andage would condemn citizens who courageously spent alot of hard-earned money to do their part in the energycrisis.

So at this point, we are faced with taking the systemdown and trying to find someone to buy it used—notlikely in a timely fashion. Or we can lower it to conformwith the local ordinance, which would put the top of thepanels no higher than 14 feet. The consequences ofthat are tremendous. First and foremost, it will result ina significant power production loss—40 to 60 percent!We’ll be back on the utility grid immediately, and back topaying an electric bill again. Second, this will mean thatthe bottom of the panels will be at a height of about 4feet, rendering it a safety hazard for our children. Andthird, it certainly lends itself to vandalism at that height.This is a major piece of costly technology. We feel veryuncomfortable having it at 4 feet, subject to anyone’sapproach. I doubt that any of those board memberswould be comfortable leaving their prized laptopcomputer sitting on a table in their back yard for anyoneto touch. This solar array is far more costly than alaptop computer.

Please, this issue is vital to all of us who are concernedabout the success of renewable energy systems. If youknow of people who can help us, advise us, or help findquality, environmentally-savvy legal representation,please contact us immediately. Time is of the essence.We would really appreciate your help in getting thevoice that we need this issue to have. Not just for us,but for all those energy pioneers who will be followingus. We’re just the first one going through the tall grasshere in Kentwood. That’s always the hardest. We wantto help make sure that those who follow don’t have tofight this battle again. Dennis and Beth Graveldingerand family • 616-656-0701 • [email protected]

Hello Dennis and Beth, What a ridiculous situation.You’re doing the right thing by trying to provide yourown energy without causing pollution or blackouts toyour neighbors. In return, they are trying to impose theiraesthetic values on you, and attempting to control youruse of your own property. Sure, we need to get alongwith each other, and that can mean compromises, butthis is too much.

How about it, readers in Michigan and elsewhere?What can we do to help Dennis and Beth educate theirneighbors and their zoning board? Send e-mail to themand to Home Power with your ideas. Solar energy canfree people, which may be threatening to the controlfreaks in Kentwood, Michigan. Let’s find ways toovercome the ignorance, and the impulse of somepeople to try to run others’ lives. Ian Woofenden

Hi Beth and Dennis, What a backward-thinking bunchof oafs! OK, now that I have had my rant, here aresome real things you can try. Find like-minded folks inyour community who can back up what you want to do,and get them to attend the next board meeting. Involveyour installing dealer and any local environmentalgroups in educating the board, local businesses, andcity officials about the benefits of renewable energy.

If things cannot be changed in the short term, you mayneed to make their mandated changes to your systemfor now, and rely on the above efforts to change theboard’s minds over the long term. If that does not work,try the initiative or referendum process. This is avaluable tool that most local governments have thatallows the public to go over the head of the governmentif it is not responsive to public needs. Michael Welch

GFCI Phantom LoadsI enjoyed Dan Chiras’ article in HP82, page 40. But I’dlike to suggest an alternative to just chucking out all theGFI outlets. After all, they have value in saving lives,even if they add a small phantom load.

My tract home has twelve GFI-protected outlets, butonly two actual GFI units (or 5 watts total if my GFIshave the same load as Dan’s). I assume (perhapsstupidly) that this is up to code (any comments byexperts?). Near my washer/dryer is a GFI unit thatprotects one standard outlet in each of my threebathrooms, as well as the backyard weatherproofoutlet. My kitchen has a GFI unit that protects standardoutlets around the kitchen and the front yardweatherproof outlet. At first I thought this was a dumb,cheapskate design to save the tract builder cash.However, learning from Dan of the 2.5 watt phantomload, I’m glad I have only two instead of twelve GFIs!

It may be worth a simple, half page article in HP toidentify brands of GFIs with little or no phantom load,and to highlight (if up to code) this ability of a real GFIoutlet to support a string of common $0.50 outlets. BestRegards, Lynn August Linse, Foothill Ranch, California [email protected]

More GFCIDear Editor, The letter concerning GFCIs (ground-faultcircuit interrupters) and phantom loads in HP83 caughtmy attention. Ward Bower at Sandia National


Letters

Laboratories and I measured quite a few receptacle andcircuit breaker GFCIs last year, including the Levitonmodel 801-6599. We were evaluating them for use withAC PV modules. None were found acceptable.

All of these AC GFCIs have an integrated circuit thatmonitors the AC hot and neutral lines for an unbalancedcurrent that represents a ground fault. Any unbalancethat is sensed over about 5 milliamps triggers the GFCI,which disconnects the output from the AC line. Thiselectronic circuit is continually powered by the AC line(inverter output in RE systems).

I purchased a new Leviton model 801-6599 last weekand tested it. The DC resistance between the hot andgrounded neutral terminals was over 20 megohms,which might indicate a very low phantom load. I hookedit up to the AC output of a Trace SW4024 inverter andmeasured an AC current of 8 milliamps into the GFCIwith nothing else connected. This indicates a phantomload (due to the internal circuitry) of about 0.96 volt-amps. I then used a Valhalla Scientific Inc. model 2000Autoranging Digital Wattmeter to measure an actualreal power draw of 0.87 watts.

In summary, the Leviton model 801-6599 doesrepresent a small phantom load of a little less than 1watt. I think that this small load is acceptable for thedegree of safety provided by the GFCI. They haveprevented many deaths from electrical shocks. JohnWiles, Program Manager, Southwest TechnologyDevelopment Institute, Las Cruces, NM • 505-646-6105 Fax: 505-646-3841 • [email protected]

Jarring NoteI found a jarring note in the article by Dan Chiras(HP82) on phantom loads. He says “My natural gas-powered backup radiant floor system consumed anenormous amount of electricity.”

I don’t understand this. He is burning fuel and notcogenerating electricity? In thermodynamic parlance,we call this “losing availability.” When you are usingnatural gas to make low-grade space heat, there is nophysical reason not to use a “topping cycle” to skim offsome of the energy as electricity, and taking the wasteheat for space heat. Anyone used to living on solar-electric panels would have all the electricity they coulduse as long as the furnace was required. Wasting thepotential is foolish.

There must be people who are burning fuel in a furnaceto heat air, and burning more fuel in a backup generatorto make electricity while throwing away the waste heatfrom the engine. This is doubly foolish.

I’m sure that all HP readers have laughed at the sillypeople from San Diego who complained that the

electric rates meant they couldn’t afford to take hotshowers, while sunshine poured free heat onto theirroofs every day. I laugh at the people who use fuel in astationary application (like a furnace or generator)without getting the most out of it. Cogeneration isn’trenewable, but it is vastly more efficient than havingsomeone burn fuel 100 miles away and throw away 70percent of it as heat while you burn fuel to make heatand buy electricity to move it around.

Cogeneration is a key to making renewables work.Because cogeneration makes electricity at the sametime as other things, it forces systems to beinterconnected. Interconnected systems are“omnivorous”; they can run from renewable energywhenever it is available, or from other supplies when itis not. This creates a guaranteed market even forirregular supplies of energy, without which renewablesare not likely to succeed. Russ [email protected]

Hi Russ, Thanks for your good comments. How aboutwriting an article on practical, small-scale cogenerationfor Home Power? Ian Woofenden

Phantoms & CF Power FactorDear HP, After reading Dan Chiras’ article aboutphantom loads, I decided to test the idle current draw ofmy own GFCIs and smoke detectors. Readers may beinterested to know that some brands are better thanothers in this respect. My GFCIs (Leviton brand) useunder 1 watt, rather than 2.5, and my smoke detectors(Firex brand) use 6 watts, rather than 12.

Also, I doubt that any code requires a house to havefourteen GFCIs. It might be more accurate to say thatthere are fourteen locations requiring GFCI protection.Since a GFCI may be wired to protect additional outletson the same circuit, careful design may reduce thenumber of GFCIs needed.

According to the 1999 NEC, the following locationsrequire GFCI-protected outlets:

• Kitchen counters: minimum two dedicated circuits,therefore two GFCIs

• Bathrooms: minimum one dedicated circuit for allbathrooms, thus at least one GFCI

• Garages, outdoor outlets, basements, sheds,workshops, anywhere within twenty feet of aswimming pool, or within six feet of a sink or fish pondor similar wet location: no minimum circuitrequirement, one circuit (thus one GFCI) could serveall.

So the bare minimum is four GFCIs. There may beother reasons why you don’t want to wire this way. The


Letters

workshop may need its own circuit, for example. But forsomeone trying to economize on phantoms, it could bedone.

On another subject, I have had a tirade brewing aboutcompact fluorescent energy consumption for sometime. It seems everyone, from the manufacturers to thegovernment to HP, is convinced that they are four timesas efficient as incandescents. I have long wonderedwhy a manufacturer is permitted to label a bulb as using15 watts when it actually uses closer to 30. The Lightsof America 15 watt Twister, for example, has fine print atthe bottom reading “15 watt/0.25 A.” 120 volts x 0.25amps = 30 watts. I have tested one with my Fluke 87,and the calculated figure comes much closer to thetruth than the advertised figure.

I stopped wondering today, after receiving my newBrand Electronics 4-1850 power meter in the mail. Iused it to test several appliances and some compactfluorescents. Strangely, the Brand meter showed the 15watt Twister to be using 14 watts, which is within themeter’s tolerance of the bulb’s advertised wattage.

I scratched my head for a while, then read the Brandinstruction manual again. It said that the metermeasures “real watts,” regardless of power factor (PF).Could the Twister (and most other CFLs) have a PF of0.5? I had heard that some electronic ballasts havepoor power factor, but I had no way of measuring it untilnow.

Power factor, for the benefit of readers who don’talready know, is an inefficiency in AC circuits caused bythe “time lag” between voltage and current waves. Thegreater the lag, the lower the PF. This isn’t exactly ascientific definition (maybe Ian has one?). PF isexpressed as a ratio of true power (watts you canactually use) to apparent power (line voltage x lineamps). A purely resistive load, such as an incandescentbulb, has a PF of 1.0 (perfect PF). An induction motormight have a PF of 0.7, or perhaps 0.8 if it’s a highefficiency motor.

So a CFL with 15 watts of “true power” puts out asmuch light, more or less, as an incandescent with 60watts of “true power.” This would not make the CFL fourtimes as efficient, however, since its PF is 0.5, while theincandescent has a PF of 1.0. At best, the CFL is twiceas efficient.

To prevent confusion (which is inevitable in any case),engineers express pure power factor loads in watts,and impure loads in volt-amperes, or VA. This is whytransformers and generators, for example, are usuallyrated in KVA.

So what does this mean for the user? Well, for the gridcustomer who measures his or her energy use indollars, maybe not much. If utility customer metersmeasure only true power, which I believe they do, yourmeter will say you used 25 percent of the power youwould have used for incandescents, and you will becharged accordingly.

On the other hand, if you are off-grid, you should beaware that as far as your inverter and batteries areconcerned, 15 watts is not really 15 watts. What mattersis the actual current draw, so get out the ammeter.

Power factor is not a concern in DC circuits, so forthose with smaller systems, I would say that it is best tostick with DC CFLs. These really are four times asefficient, and you also eliminate inverter losses.

This also calls into question the claims about how manypower plants we could shut down if everyone were touse CFLs. If people are using true power in theircalculations, they overestimate grossly.

That said, I use CFLs exclusively. During the summer,they probably are four times as efficient, once youfactor in the reduction in waste heat that air conditionersmust remove. They are the wave of the future, soeverybody might as well start using them now. Thankyou for publishing such a wonderful magazine. Eric Kay,Austin, Texas • [email protected]

Hi Eric, Power factor is confusing. But it is not true thatoff-grid users are having to supply compact fluorescentlamps with twice the rated power. The inverter has todeliver twice the AC current, but a good inverter can dothis without drawing twice the DC current from thebattery.

What is going on? There is twice as much currentsloshing around in the AC circuit, but it is not deliveringany more power, because of the timing. Some of thetime the load is actually feeding power back to thesource, because the direction of current (flow) reversesat a different time from the direction of the voltage(push).

The higher current means more loss in the resistanceswithin circuits, transformers, fuses, and everythinginvolved in power transmission, but it does not have tomean you are using much more energy from the source(battery, wind turbine, solar panel). A bad power factorlowers the efficiency of the system slightly, but a goodsystem will cope well. “Real power” (W) is real powerand “apparent power” (VA) is actually only apparent.Check on this by measuring the actual current from thebattery when you are using some of these lamps. HughPiggott • [email protected]


Letters

Nix on Manufacturer Input to NECSteve Willey responded to Code Corner, HP81 aboutusing aluminum wire for DC. And John Wiles thenresponded to that with, “We may need to put some sortof advisory (not a requirement ) in the code if we cansatisfy any objections raised by the cablemanufacturers.” If the NEC is supposed to protect thepublic, the cable manufacturers shouldn’t have any sayin it. Homer Welborn • [email protected]

Hello Homer, The code is not only implemented toprotect the public, but to protect the operators andmaintainers of electrical systems. There are alwaystradeoffs to be made when requirements are added tothe NEC. They involve costs, complexity, availability ofmaterials, components, systems, and most important—safety.

As I have stated on many occasions, the code isformulated by the electrical products manufacturers, theelectrical inspectors, electrical users, UnderwritersLaboratories, IEEE, the national labs, the insuranceindustry, and a host of others. Documented,substantiated, proposals submitted to the NFPA arecarefully reviewed over a three-year cycle by allinterested parties.

All of these parties carefully review the proposals andjointly decide whether the safety concerns outweigh thecosts associated with implementing the proposal. Thereare two review and comment periods available to thepublic, and the inputs on each proposal may benumerous. There are few “knee-jerk” requirements thatget into the code. Thank goodness for that—it is bigenough as it is. John Wiles • [email protected]

Homer, Actually, getting the manufacturers’ input mightbe a very good idea. Here’s why: While the folks thatwrite the code don’t exist in a vacuum, they are not, byand large, wrenches. Their opinions and interpretationsare based more on theory than experience. A pity, butthere it is. The cable manufacturers, in this case,respond to market pressures. Wrenches buy theirproducts. If they don’t give the wrenches what theywant and need, they go out of business. So in aroundabout way, involving them in the process brings insome wrench input as well, which is a good thing. Bob-O Schultze • [email protected]

Interested In Helping With Guatemalan Solar?Hi Richard, I really enjoyed the article on the homebrewbiodiesel in Humboldt. Here in Thailand, villagers havebeen mixing coconut oil (20 parts) with kerosene (1part), and can burn it directly in diesel engines!Apparently coconut oil is pretty light already anddoesn’t need the esterfication process.

See the letter below—This gentleman really wantssomeone to come down and check out the scene andguide this project from a technical viewpoint. Peoplewith Home Power technical skills are in high demand indeveloping countries! Cheers, Chris [email protected]

Uaxactun is an 80+ year old village in Peten,Guatemala. There are 140 families, 65 with solar-electric panels already on their houses (for 2-1/2 yearsnow). This is a very conservation-minded community.They manage 83,558 hectares of Maya BiosphereReserve as a biological corridor in the heart of the MayaForest.

American oil companies and the Guatemalangovernment are pressuring development, starting with“social development” in the form of a water pumpingproject, which the villagers want, but which is beingstalled because the villagers are fighting plannedpetroleum/military development nearby. So, thevillagers want to finish the water pump themselves, withsolar (they have a generator option, but would ratherstick with renewable energy). And they want to gofurther and become a fully solar-powered community(they’d like modest household lighting andelectrification). Development is coming, and they wantto shape how it happens to them. And they want to gosolar! Contact Roan Balas McNab, WildlifeConservation Society, Guatemala Programs502-926-0569 • [email protected]

I’m On Your Side...I too am of the opinion that small-scale RE systems canmeet the needs of society. If we follow the example ofthe Internet, we’ll network all these small clean systemsand get a green grid. Pretty cool. Let’s change the worldone house at a time.

Now on to what really sparked this letter. I was readingthe April/May 2001 issue downloaded from the Weband couldn’t get past the first few paragraphs of “BothSides Now—Hybrid Vehicles.” I was certainly glad toread “(Author’s note: This reflects the somewhat cynicalopinions of this writer, which are not necessarily thoseof Home Power staff and management.)”

Until battery technology is quick to recharge (say 5 to10 minutes) and they are made of less toxic stuff thanlead, nickel cadmium, or other more exotic materials, Ithink the hybrid is the answer. I commute to work, a 220km round trip in a country that has no high speed rail(Canada), so here are my requirements for a practicalelectric car. I could take the bus, but it is too expensive;there’s something wrong when I can drive my car forless than I can ride the bus with 45 other people. Oh, Idrive a diesel VW for a commuter, and I carpool.


Letters

For me, an electric car must be able to drive at 100km/h for an hour and a half in -20°C temperatures. Itmust be able to do this with the headlights on, andprovide heat for the interior as well as power for the reardefroster. While I’m at work, the vehicle will sit in aparking lot (with no electricity available) for eight hoursat -10 to -15°C), after which it will be called upon tomake the hour and a half trip back home under thesame conditions. Today’s battery technology just is notup to this kind of task.

It is unfortunate that not everyone lives in a year-roundwarm climate with plenty of sunshine, so truthfully, anall electric vehicle for the mass market does not seempractical, yet a hybrid works quite nicely. I’d love to beable to drive an electric vehicle to and from work,generate my own power to re-fuel it, and make my life alot less expensive, while at the same time keepingthings green. One must keep in mind that an electricvehicle today simply offloads the emissions to the grid,which is powered (for the most part) by nuclear, naturalgas, coal, or hydro.

I have to tell you that I am also a car buff—sorry, I lovethem. Making them green and keeping them fun wouldbe a hoot. I drive a diesel to work, but I also own a V-8Firebird and I’m amazed at its efficiency. Yup, you readit correctly—an efficient V-8 muscle car. Look at the VWand Firebird side by side.

The mpg to power ratio puts the Firebird way ahead ofthe Golf, but the Golf can burn biodiesel (something I’mexperimenting with) and its (dino) fuel costs 66 to 69cents a litre... about CDN$3.00 an imperial gallon onaverage compared to the Firebird’s 84 to 89 cents alitre. For the V-8 to cost the same to operate as theGolf, it would have to get around 70 mpg!

Overall I love Home Power magazine, keep up the goodwork. Now I’m going to try to get past the author’s biasand see if there’s any salvageable info in that article.Kindest Regards, Stephen [email protected]

Hello Stephen, I’m glad you were interested in theHonda Insight article, and I hope you read the ToyotaPrius article in the next issue as well. If so, you foundthat I agreed that hybrids serve a useful purpose forsome situations.You certainly are a perfect example ofa driver for whom a hybrid would be an excellentchoice, due to your long commute.

As for issues of battery toxicity and power plantemissions... funny you should mention them. I justhappened to address those topics in my article in thisissue (see page 98 ). I also notice that, as I mentionedin the hybrid articles, you are one of many householdsthat have multiple cars. Perhaps one of your fleet that isused only for local errands could be pure electric.Biodiesel is also an excellent alternative.

No, electric cars cannot fill everyone’s needs all thetime. But there are a huge number of vehicles on theroad that could be pure electric, without cramping theowner’s style in the least. If we only replaced those carswith electrics, it would make an enormous difference inour air quality and our petroleum dependence.

By the way, since you are in Canada, I hope you willcontact the Vancouver Electric Vehicle Associationlisted in the Access section of my article in this issue.Even if you live on the other side of the country, theycan supply useful information, and may be able to putyou in touch with an EV club near you. Shari [email protected]

Hi Stephen, I have two major disappointments aboutthe two “hybrid” vehicles on the market. First is that theyare completely gas powered.You cannot plug thesecars in. It would be nice if you could use RE or evengrid electricity for battery charging, since it is bothcleaner and more convenient. Second is that theelectric component is so minor. The Prius’ battery isonly 110 pounds, while the Insight’s is half of that.These are small battery banks, so they primarily offer a“boost” to the car for acceleration and some slow-speedoperation with the Prius. However I look at it, these“hybrid” designs seem to be completely stacked in favorof non-renewable fuel use.

These new vehicles are certainly a step in the rightdirection, but I don’t see it as a big enough step. But, it’snot an either/or situation. We can have these types ofvehicles and pure electrics, since there are manydifferent needs to fill. Ian Woofenden

Lightning and BoilersRichard, I just noticed your comment in HP83 on page142 on boiler systems, and page 151 on lightningproblems. I have short comments on those two topics toshare experience and opinions that are exceptions towhat you stated.

On boilers, those I have encountered have been badphantom loads, though one was possible to modify byusing a line voltage thermostat on the AC side of thetransformer. But the boiler does not store water, sothere is an extra pumping stage plus the control loadsthat makes them electrically inefficient. Of course, agood quality tank style gas water heater eliminates all

Car Efficiency Comparison

Make & Model Fuel Type Horsepower MPGVW Golf Diesel 52 47Pontiac Firebird Gas (92+ octane) 305 35


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the electrical problems of the boiler, but trades them forinefficiency of BTUs going up the stack.

On lightning, my experience says that systems withburied wires have the most lightning damage toinverters and sometimes charge controllers. Wiresgoing underground to PV, or underground AC wires tooutbuildings always seem to be present in lightningdamaged systems. We recommend placing thearrestors on these wires where they enter the powerroom. It seems that a lightning strike to a tree will sendemf ripples centrifugally outward like ripples in a pond,and a wire parallel to those lines will pick up theinductive pulse. In fact I have seen the sparks jump outthe ends. Systems with modules on the building and nooutbound wires at all have to suffer a direct hit to bedamaged. That said, lightning—being unpredictable—will prove us both wrong.

And a request: I have long been sending folks to theCalifornia state energy Web site for comparisons ofefficiency for appliances like refrigerators and freezers.They seem to have cancelled that page now, and I findmore difficult to use data atwww.energy.ca.gov/efficiency/appliances and alsowww.energystar.gov/products in spreadsheet form. Isthis the best you know of presently?

Finally, thanks for the guide to RE incentives atwww.homepower.com/stateincentives.htm—it’s justwhat customers need. I will be promoting that in ournext Backwoods newsletter. Steve Willey, BackwoodsSolar Electric Systems • [email protected]

Hello Steve, Thanks for this information on boilers andlightning. I totally agree with you on the fickle nature oflightning. My experience with buried conductors hasbeen the opposite of yours. Perhaps this has to do withsoil composition and moisture content. The more I hearfrom others about lightning damage, the more I realizethat our understanding of lightning is akin to the parableof the five blind men describing an elephant.

I find the best source of info for efficient appliances is:American Council for an Energy-Efficient Economy(ACEEE), 1001 Connecticut Ave. NW, Suite 801,Washington, DC 20036 • [email protected] • www.aceee.org Richard Perez

Guerrilla Inverters Still AvailableDear friends of guerrilla solar, I have heard of lots ofdisappointment in our world of rebel solar becauseTrace Engineering is no longer selling their MicroSineinverters. These little units allowed guerrillas like us toslap together a 100 watts of modules, stick them in thesun, and plug them into our household circuits, for ourown use or to turn the meter backwards. They are safe,

and they work pretty well. It is too bad that Tracestopped selling this great little tool.

But the very same OK4U-100 inverter is still beingmanufactured by the maker in The Netherlands, and isstill available. They have about 1,000 in stock that carrythe original UL listing. And once those are gone, thenewer units’ safety is still certified by the strict EuropeanCE and by the Dutch Kema Keur rules. They are alsostill making the OK485 computer interface to allowmonitoring and fine-tuning of the inverter’s operatingparameters.

They can be ordered individually or with price breaks forgreater numbers directly from the manufacturer.Shipping to the U.S. is no problem. To order or getpricing information, call, write, fax, or email to: NKFElectronics B.V., PO Box 415, NL-2800 AK Gouda, TheNetherlands • +31 182 592 497 • Fax: +31 182 592 123 [email protected]/electronics/photo.htm. Sincerely, MakaRukus & Jenny Freely, solar guerrillas

Net Metering Help for MissouriDear Michael, I live in a state that I believe could careless about renewable energy. Missouri has no netmetering law, and I would like to start writing some ofthe representatives in my state to encourage them topass the laws I need. I want to have my own gridintertie system and keep my electric company frommessing with me. I’ve looked at the net metering link onyour Web site, and I’ve seen what some states haveand what others are proposing. I don’t know the politicsand what’s fair between me and my utility. I figure this issomething you guys talk about all the time. What I’mwanting is for Home Power to tell me what I shouldpropose in my letters so I can help the energy-conscious in my state who have my interest, but whowill never write a letter. Can you help me? Donald R.Culver, 15448 Old 40 Hwy., Higginsville, MO [email protected]

Hello Donald, We are printing your letter so that othersin Missouri can contact you and help out. A goodresource for net metering laws is Tom Starrs 206-463-7571 • [email protected]. Michael Welch

Alastair’s Desulfator CircuitHi Richard, Alastair Couper has suggested that I get intouch with you to let your readers know that parts kitsare available for his battery desulfator (see HP77, page84 or www.shaka.com/~kalepa/desulf.htm). I’vemodified the linked circuit to use a programmable microcontroller—a “Stamp”—to drive the FET. The BASICStamp 1 is a small computer (about 4 times the size ofa 555 timer chip or a 28 pin DIP) that runs ParallaxBASIC (PBASIC) programs. The BASIC Stamp is


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programmed via a custom cable that attaches to yourcomputer’s parallel printer port.

I sell the parts kits for both the original and Stamp-driven circuit for those folks having a difficult timefinding the parts (seewww.shaka.com/~kalepa/desulfparts.htm).

Motorcycle batteries seem to sulfate just by looking atthem. I have saved a ton of money desulfatingmotorcycle and UPS gell-cell batts using the originalcircuit. The Stamp is a bit easier for most folks to setup. I am currently developing a battery analyzer(conductance testing) using the Stamp and a small partof the desulfator circuit:www.shaka.com/~kalepa/gbook.htm. The Stamp is ahoot to play with. Have fun! Don Denhardt, ClintonTownship, Michigan • [email protected]

Solar Clothes Dryer to the RescueHi, Richard, My daughter-in-law just dropped off theFeb/Mar and Apr/May issues of your magazine. I hadn’tlooked at one for a while, and I was very impressed withthe quality of your information and everything else.Good work. I especially was impressed by the articleabout passive cooling in hot, humid climates (althoughthere is obviously a lot more to be told in the nextissue). It was an excellent primer in the basic physics ofenergy, heat, etc.

In the Feb/Mar issue, you wrote, in Ozonal Notes, onthe subject of infrastructure, and how we will eventuallyproduce a lot of our energy with PV, but with the utilitycompanies still being involved in transmission. You alsomentioned that, eventually we could use some of thissolar energy to produce hydrogen, which could then beused in pure hydrogen fuel cells for those times whenthe sun isn’t shining. I agree with this idea; however, Ialso think that, in the short term at least, perhaps theproblem of no insolation at night could be overcome bystoring energy by pumping water up to storage sitesduring the day, then retrieving the energy by running thewater back through turbines for nighttime production. Ifwe put storage facilities at a high enough elevationabove the pumps and turbines, we could minimize thesize of the storage facilities.

Another thing: recently on the Jeff Golden show onNPR, a man called in, and claimed that if everyone inCalifornia stopped using their clothes dryers, therewould not be an energy “crisis.” Nothing else. I stronglysuspect this to be true. Flash—I just went to your PDFon load calcs, where your two example families eachrun their clothes dryers for four hours per week. Theloads given in your example were for a gas dryer, Iguess. I didn’t see any figures for electric clothes dryerson your site, so I found a number on another site: 4,350

watts. This seems reasonable; a dryer circuit requires athirty amp, 240 volt circuit. So if we assume there are8,000,000 families in California, and all of themconverted from electric to solar clothes drying, thatwould be 8,000,000 x 4.35 KWH x 4 hours per week =128 gigawatt-hours per week.

Another way to look at it is, assuming that an averagefamily uses 1 KW continuously, on average (a numberI’ve heard kicked around, but can’t confirm), thenswitching to a solar clothes dryer would save about tenpercent of their total energy use. Rolling blackouts areonly occurring when the “margin” at the power plantsgets down to, what, 1 percent? This means that just theclothes dryer issue would give them plenty of margin tostop the blackouts, while we convert to RE sources.

I realize that everyone in California doesn’t have anelectric clothes dryer, but even if they have gas dryers,they still use a similar amount of energy. I also realizethat there are a few brave souls who already useclotheslines, but as far as I can tell, we’re a tinyminority. One of the callers on Jeff Golden’s programsaid that he gets teased because he uses a clothesline! Another says that clotheslines are prohibited in herneighborhood.

I have another question: since California pays up to halfthe cost of a PV system, do you think it is prudent for usOregonians to wait on purchasing a PV system untilOregon follows suit? After all, we’re a progressive state,right?

Along these lines, do you know of any efforts beingmade to influence the Oregon Energy Department, orlegislature, or governor to move in this direction? Whatcan I do? Who should I write? Who should I shake?Great magazine you guys have going there. Thanks,Malcolm Drake, Grants Pass, Oregon •[email protected]

Hello Malcolm, I think your calculations regardingelectric clothes dryers are right on target. In sunnyCalifornia, a simple, outdoor clothesline is a real winner.I’m often distressed when I receive email fromCalifornians living in subdivisions that prohibit outdoorclotheslines. Get a grip, folks!

I wouldn’t hold my breath for Oregon to have a PVbuydown program similar to California’s—Oregon justisn’t that rich. But Oregon does have some veryattractive RE tax incentives. Contact ChristopherDymond, Oregon Office of Energy, 625 Marion St. NE,Salem OR 97301 • [email protected]

In terms of political organizing for RE programs inOregon, contact John Patterson of the Oregon Solar


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Energy Industries Association (OSEIA)[email protected]. Richard Perez

Electric TricycleHi Richard, I liked the “Electric Tricycle” article verymuch (HP83, page 84); it gives enough detail to inspiredoing your own not identical but similar design.

There is one thing that gives pause—the charger circuit.There is a shock hazard with this design, and whereasI’m glad to see that people are still windingtransformers, this is an auto-transformer with no lineisolation and where one side of the AC line is directly tothe battery/motor. In the U.S.A., 220 volts is either sideof neutral rather than one side being neutral.

Also, it is worth reminding people that they can dietouching twelve (even four!) batteries in series. It onlytakes about 7 watts to kill you (locked up chest muscle).I hope no one gets hurt and we continue building stuff,but I continue to be concerned that HP doesn’t seemconcerned about publishing material that may behazardous to inexperienced users without safetydisclaimers. I want HP to continue to publish forever(Fuel Cells From Plastic Wrap?).

In this particular article, the charger isn’t a requisite partof the fundamental design. On the other hand, I’mwondering where all these cheap Chinese drills are(grin). Anyhow, thanks for the wonderful magazine!Premena • [email protected]

Hello Premena, You are correct, the autotransformerdesign carries with it a shock hazard. Folks eitherbuying or winding their own transformers should usemodels with fully isolated windings, notautotransformers. My apologies for letting this slip by inprint without warning folks. Richard Perez

Hydrogen TechnologyThanks for a great magazine. I have subscribed toHome Power since issue #2, and all issues since arepart of my library. I have gained most of my knowledgeabout alternative energy by reading Home Power.

I live on a farm (off the grid since 1992) in centralPortugal. I have a 2.6 KW solar-electric system thatsupplies all the electricity for my two houses (one is aguest house). The energy is stored in two battery banksof 900 amp-hours and 1,850 amp-hours. I also have abackup generator, but I have only used it for 800 hoursin nine years. Keeping in mind that it is cheaper to saveenergy than to produce energy, I only use energy-saving lamps, and always buy the most energy efficientappliances I can find. My houses have all the modernamenities like any house in the city. I also have asubmersible pump, which lifts all my water from a 70

meter deep well. So far, I always have had enoughelectricity, even in winter.

This winter it was a different story. It started raining inearly November and it did not stop until the beginning ofthis month. We had storms and floods in Portugalunknown in the history of this country. In six months,there were only fourteen days of sunshine. My solar-electric system survived this extreme weather, but mydiesel generator broke down. For the first time, Iexperienced an energy shortage.

The experts say that this extreme weather is only thebeginning, and that it will get worse. We have to livewith this kind of weather extremes in the future—theconsequences of global warming. It seems that theclimate change is accelerating. Higher temperaturesmean more evaporation. The more water goes up, themore comes down. Higher temperatures also meanmore heat radiating from the surface, creating morepowerful storms.

If there is no sunshine for six months of the year, I mustreconsider my energy supply. I have no stream nearbyand therefore no hydro power option. I live in a valleyand I cannot make use of wind power. In the summermonths my two battery banks are fully charged ataround 11:00 in the morning. If only I could store all theelectricity that I could harvest after 11:00, it could beenough for the long winter.

The answer could be hydrogen storage and fuel cells.How long will it take until I will be able buy thenecessary hardware, as I now buy charge controllers,inverters, and batteries? I would very much appreciate ifyou could run some articles about the availability of thehydrogen technology for home power applications. Bestregards, Robert Kuchta, Tábua, [email protected]

Hello Robert, We ran a fuel cell article in HP72 and thesituation has not changed very much since then. I wishI had a crystal ball and could predict when fuel celltechnology would replace engine-generators as backupenergy sources for RE systems. My best guess is thatwe are at least two to five years from this happening.Richard Perez

HP Advertisers:Take NoteHello everyone, Today (5-1-01) I made the decision toput Hydrocaps on two flooded deep-cycle batteries inthe solar-electric system that powers my ham radio rig.Naturally, I grabbed the latest issue of Home Power tofind a friendly dealer for this product by going to theirWeb site.

Guess what? This simple task consumed more thanone hour! And why did it take soooooo long for me to


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part with about $60 of my money? Because not toomany of the advertising sites have enough brains to putsearch functions into their sites!

I and others are not going to spend stupid amounts oftime wandering around in product listings and othertrappings of a Web site. If your living depends on sellingthe various products of renewable energy, don’t wastemy time! Get smart! Review your site and make surethat the search function is right out front, or your site willnot make it into my (and perhaps others’) favoritesfolder. Bill Bowes, N7MOB, Federal Way, [email protected]

Todd Engineering $$Howdy Home Power, I, unfortunately, purchased twoTodd Engineering chargers last year. The chargersfailed and the folks at Todd were real nice. They sentreplacements and took a credit card number toguarantee the return of the defective units. I returnedthe units last year, and I thought the matter was closed.

I was wrong. They charged my credit card for one of thereturned units. I tried for three weeks to contact ToddEngineering to no avail. Finally, I challenged the chargewith my credit card company. Soon I heard from ToddEngineering’s bank. They are out of business and thebank has taken over their accounts. They are chargingeverybody everything they can because Todd’sproblems also led to a huge debt that the bank wantsrepaid.

The person I spoke with at the bank was very nice andagreed to cancel the outstanding debt that they showedon my account. I suppose many of your readers havehad similar problems. My main reason for sharing thisinformation is to pass on the contact information for thebank. You cannot get through to Todd because they aregone. The contact is: Kenneth E. Lust, Vice President,Special Assets Manager, National City Bank of Indiana,Fort Wayne Office, 110 West Berry St., Fort Wayne, IN46802 • 219-461-7404 • Fax: 219-461-7471.

Please pass this info on to your readers who might bepulling their hair out trying to get in touch with ToddEngineering. Please withhold my address because Idon’t want my whistle blowing to alter my status with thebank. Thanks. (Name withheld at writer’s request)

To Light Our Darkest HourGreetings, I have been following HP since my interest inRE turned from fantasy to fact in 1991. Recently, I builta small 100 watt RE system to provide energy in theevent of a blackout. Power outages are not common forAustin Texas. Usually when they occur, it’s due todowned power lines from high winds. On May 20, wehad a severe storm blow through our northeasternAustin neighborhood.

As many as 25,000 customers were without electricity.The darkness came across my block as power linessnapped in the 80+ mph winds. The only light was fromthe lights reflected from the city and the light in myhouse. Thank you HP! If it were not for your insightfulmagazine, I would not have been able to light ourdarkest hour. My system was assembled for less thanUS$500.

I would like to add on a sad note that the solar-electricpanel I used in my system was taken from me by thehigh winds. Ironically, it was just after I read an oldarticle on how to properly mount PV panels. Cheers,Thomas, Austin, Texas • [email protected]

GreedRichard, Renewables are great, but the Californiaenergy problem is a lot more about greed then it isabout a real shortage of electrical energy. The PUC gotus into this mess and I really doubt if they can get usout. Thanks for keeping Home Power available on thenet. I hope you keep your advertisers informed of thisunbelievable benefit. Mike, Vacaville, [email protected]

Apartment PV Retrofit?I’ve begun searching for any PV product or prototypethat would work in an apartment building with excellentsolar exposure. I’m envisioning a product like mini-blinds, with each blind turning sunlight to KWH (with orwithout battery backup). I have about 39 square feet ofsouth-facing glazing, with no obstructions, and thesame east-facing, for a total of 78 square feet. In spiteof the view of Mt. Rainier from two windows, I oftenhave to keep my blinds partially closed to block glare oncomputer screen. Also, if I return to working five days aweek away from home, the blinds could be closed withno loss of light or view.

Is there anything like this under development? I wouldbe happy to cooperate with product developers if theyneed a test site. With more than fifteen yearsexperience in energy efficiency and renewable energy(including solar site survey thirty years ago), I would bea conscientious product tester. Of course, I would preferthat the building owner take advantage of the electricutility’s 70 percent loan to weatherize this 1912 building,and then go a step further and add solar rooftop panels.But she has not responded to the info package Iprovided. Therefore, anything I can do with the interiorof my apartment that does not violate thetenant/landlord contract would be my next best option.

It seems to me that window washers and mini-blindcleaners would be proactive on any emerging productthat turns window treatments into solar collectors.Looking forward to reading an article in HP if the


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industry is already heading this way. Thanks. DulceSetterfield • [email protected]

Hello Dulce, Several PV manufacturers, notably BP, aredeveloping semi-transparent photovoltaic glazing.These thin-film products are being very slowlyintroduced into the commercial, building-integrated PVmarket. There are no similar products on the nearhorizon for the residential market. And if and when theydo arrive, they’ll probably be in the form of windowglazing. So installing the systems will mean replacingthe windows—not a solution for people in rentalsituations.

I’d suggest approaching your landlord again about arooftop PV array. With all the energy issues in the news,they might be more willing to work with you. If yourbuilding has a flat roof, the array could be ballasted(weighted down) and the roof membrane wouldn’t evenneed to be penetrated. I’ve been thinking about writingan article detailing the status of building-integratedphotovoltaics. Thanks for your input. Joe Schwartz

Voltage DropDear Home Power, Code Corner, HP81 dealt with sizingwire for a small simple system. As usual, Mr. Wiles did avery thorough job of explaining the issues and showingsample calculations. As sometimes happens, I wouldreach a somewhat different conclusion. I’ll lay out theissues as I see them.

1. I agree with John that 5.5 volts drop (23%) on a 24 VRE system is way too much.

2. John describes what I think is more accurately calleda 34.6 volt system, and not a 24 volt system, basedon the peak power point (per ULCI703) and nobattery, with a 24 volt load (motor/pump).

3. Using John’s calculations, the 5.5 V drop (usingpeak power point as John did) leaves us with 29.1 Vat the motor—over 21 percent higher thannameplate. If the 2 percent drop is used, the motorwill see about 34.1 V—about 42 percent higher thannameplate. On a clear cold winter day, the voltagecould be higher yet, while a hot hazy summer dayreduces the voltage. As an engineer who hasworked with two different motor manufacturers, thisconcerns me. Most 24 volt motors should work justfine up to 28 volts or so, with higher voltagesresulting in reduced life. Check the motor/pumpinformation. Many solar pumps will work PV directwith up to 30 volts. Higher PV current output can beachieved under some conditions, but it would bevery surprising to end up with a low motor voltageunder high current conditions.

4. Depending on the type of motor and pump, thehigher voltage can result in short motor life due tohigher loads at high speed, brush arcing andexcessive wear, and a host of other factors. Highvoltage, and hence high speed, can also quicklywear out some types of sliding vane and diaphragmpumps. Under low light conditions, the poweravailable can drop substantially, stalling out themotor.

So what do we do? I would recommend using a #14cable. With more information on the motor than is givenin John’s prelude, we could fine tune this. A lower ratedmotor current than 4.33 amps might convince me to usea #16 control cable, if this was my own system.

The user should talk to a local RE dealer or electricalsupplier. They can probably obtain a suitable cable, ormay suggest a conduit from the panels to the ground toeliminate the need for sunlight resistance. Thedisconnect could then be located in a weatherproof boxadjacent to the panels, with the transition from conduitto buried cable made at the junction box. Lowtemperature (60°C) wet-rated wire can be used fromthe box to the pump. Your final purchase may involve alinear current booster. That will keep the pump pumpingunder conditions that may not normally allow the pumpto operate. I’d much rather see the few hundred dollarsspent on an LCB than heavy wire—I believe you’ll getmore water for your buck!

One last issue from the article I’d like to clarify involvesgrounding. In the same Code Corner column, Johnunintentionally suggests that the negative “may be”attached to the ground rod at the PV, and “will be”connected to the ground rod at the pump location. Ingeneral, I suggest avoiding ground loops. I wouldground the electrical system at one location only, if atall. I would not ground the negative at both the PVmodule ground rod and at the pump. Bonding both themodule frame and pump to ground is a different issue.Patrick Cusack, Arise Technologies, Waterloo, Ontario,Canada

Hello Patrick, It is good to see these types of letters inHome Power from our friends in Canada.You raisesome good points. It was not my intent to presentinformation on designing a water pumping system, butto show how voltage-drop calculations are made. Whilemy experience with PV water pumping is somewhatlimited, I do not recall any limitations on the maximumvoltage, other than the nominal system voltage (12, 24,or 48 volts). I have seen few discussions of voltage dropor high open-circuit voltages in cold weather. As thevoltage goes higher (above 48 volts nominal) with theelectronically commutated designs, I suspect that the


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voltage range may be more carefully restricted. I'll leaveit to the PV pump suppliers to discuss this in moredetail.

As far as the comments on wear and tear onconventional DC motors operating at higher voltages, Iagree with Patrick's comments. We must keep in mindthat many of these PV power pumping systems do notuse conventional DC motors, but use solenoid types ofpump drivers and electronically commutated ACmotors. I agree again with Patrick—check with thepump supplier.

Copper is pretty cheap these days. Up-sizing theconductors should always be evaluated in a cost vs.performance tradeoff, keeping in mind that the upgradeis a one-time cost that must be balanced against thepower and energy losses over thirty years or more.Power lost due to increased resistance in smallercopper conductors is lost forever. Even when a currentbooster is used, they too, can benefit from higher powerinputs (less voltage drop). The output power (highercurrents at lower voltages) of such a device will alwaysbe limited by the input power (usually at higher voltageand lower currents), minus any losses in the currentbooster. When the input power is reduced by wirelosses, so will the output power.

Where the PV array is located some distance from thepower electronics/battery/pump, it is acceptable to bondthe negative circuit conductor to ground at the PV arrayand at the power center, as long as no equipmentgrounding conductor or other metallic path is usedbetween the two locations. This saves the cost of one Get A Job!

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conductor (the equipment-grounding conductor), andthat money can be used to upgrade the size of thecircuit conductors. See "Grounding the South 40" inCode Corner, HP74 and NEC section 250-32.

I visited the local building supply store yesterday andfound that all of their THHN was dual marked THWN-2(an excellent conductor for use in conduit), and that theprice of that wire was less than conductors with lesserratings from other sources. In many cases, the largerproduction runs and demands in other industries for thebetter cables gives those of us in the PV world theopportunity to get the best cables at a lower price thanwould otherwise be possible. John Wiles, ProgramManager, Southwest Technology Development Institute,Las Cruces, NM • 505-646-6105 • Fax: [email protected]


don’t go to

410-391-2000


Ozonal Notes

Deja VoodooRichard Perez

©2001 Richard Perez

On 24 May 2001, I received the following email from aHome Power reader:

“Hello again, Richard. Since I got your four Solar CDs frommy son for Christmas, I have spent many hours readingthe back issues. One page stood out today—HP22, page4, and I thought you might want to be reminded of it.Perhaps you could run it again and save yourself a littletime! Reminds me of the old saw, “Like father, like son.”Hope to see you at the MREA fair in June. Cliff Anderson,Brooklyn Park, Minnesota.”

I didn’t remember what Cliff was referring to, so I pulled outa copy of HP22 and looked. Here is a verbatim reprint ofthat editorial. We first printed it in the April/May 1991 issueof Home Power.

Bush’s Energy Non–Policy for the Suicidaland Terminally Stupid

Bush’s new energy policy assumes we are fools with adeath wish. There is nothing new in drilling Alaska till ithurts, or in building more nuclear power plants. This is thesame short-sighted BS that has gotten us inenvironmental trouble and into war. Let’s look at the facts.

Sucking Alaska DryThere really isn’t that much oil in Alaska. How much? Well,look at it this way. Alaska contains less oil than we’d havesaved by sticking with the EPA automobile mileageguidelines modified in the 1980s. When the governmentlessened these EPA requirements, auto makers stoppedmaking more efficient vehicles. This one dumb move hasconsumed more than all the oil in Alaska. Drilling Alaskaonly postpones the inevitable, destroys Alaska, and pollutesus all in the process. We need alternatives to oil burning,not more oil.

More NukesNo one is building new nuclear power plants. Nukes underconstruction are being decommissioned. The reasons forthis are simple: One, no one knows what to do with theradioactive leftovers. Two, the nukes operating now aremore expensive and have more down-time than any othertype of power plant. Three, when the Washington PublicPower System (WPPS) failed financially, it took the entirenuclear power industry with it. The third reason is what hasreally stopped nuclear power. The WPPS bonds (AAArated municipals) went from valuable to worthless in a

single day. No one will finance new nukes because theyare financial disasters. Let us give thanks for small favorsbecause if nukes were cost-effective, then we’d have todeal with their radioactive waste. And no one has theanswer to that.

Something Else?Yes, we want something else! We’re tired of the same olddreck that is visibly poisoning our planet and picking ourpockets. We’re ready to do whatever it takes to give thisplanet a sustainable energy future. And here’s what ittakes.

Use Renewable Power SourcesMake power from sunshine, wind, and falling water. Thereare between 30,000 and 50,000 households now doingthis in America. Home power producers have their ownpower company. No monthly bills, no blackouts, and nopollution.

Conserve ElectricityIf you can’t get your power from a renewable source, thenconserve every watt-hour. Use efficient appliances. Turnoff appliances when not in use. Be aware that the cost ofgrid power is much higher than your electric meter shows.Treat every watt like it will come back and bite you—because it will. Coal, nuclear, and oil power plants allextract a high price from our environment.

Drive CleanKeep your vehicle in top shape. Drive only whennecessary. Drive slowly. Keep your tires pumped up. Usean electric vehicle. Demand automakers produceemission–free vehicles. Then buy one and smile as youdrive it.

A Green DreamGreen certainly, but this is no dream. Look at the articles inthis issue alone. These are people who are living theGreen Dream. Check out Huckleberry Homestead on page6—they’re doing it. Check out the electric car on page85—they’re doing it. If we just plain ole’ regular folks canaccomplish this on our budgets, then government and bigbusiness has no excuse. It’s a dream until you decide tolive it...

After reading this, I got slack jawed. Did I really write thisten years ago? I thought about opening up a hotline—call1-900-Solar Psychic. Then I realized that I’m not psychic,it’s just that nothing has changed in the U.S.A.’s energypolicies during the last ten years. About the only thing outof date in that editorial is the number of RE users, which iswell over 180,000 now. As far as our government’s energypolicy, it’s the same old BS.

President Bush is following his dad’s ten-year-oldpolicies—more oil, more coal, and more nukes. Is thiseffective? Hardly. We are now having utility blackouts, andthe price of gas is higher than it ever has been. We havetrain loads of nuclear waste waiting to cruise the trackslooking for a home.

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Na

t ur a l B o d y c

ar

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Psycho-logicDark Age MindsetJason Powell ©2001 Jason Powell

A psycho-logic, Dark Age mindsetmanipulates many of the two-leggeds

A psycho-logic, Dark Age mindsetmasquerades as yet another emperorwearing yet another new skinIn Washington, it’s Bush 2, son of Bush 1same stage, same storylinemore “family values”from the family with killer connectionsCIA, defense industry, big oil that isNEW and IMPROVED!sugarcoated (lines of junk)ON SALE!BUY NOW!

(The children watch)puppets of politick playhand in hand with priests of industry,making war and drilling for oilin the Garden of Eden

(The children watch)the stewards turn junkiepumping the juicelike a mainline habitnever getting enough,even though it kills

Sin, sham, or shame,what’s the difference?

(The children watch)a psycho-logic, Dark Age mindsettoasting tomorrows, as in burning futureswith clean air and clean water sacrificed,blown away, as in wasted,by the engines of profit and progresswho needs clean air and clean water anyway?

(The children watch)a psycho-logic, Dark Age mindsetbabbling on and onblah, blah, blahin crazed, grinning self-delusionspewing a litany of garbage philosophy“acceptable” levels of pollutionand “clean” coal brainwash propagandais the junkie’s junk trying to shoot youin the headpsycho-logic warfare

On sale!Buy now, while supplies last!hits of oxygen and plastic bottled water(hey kid, get to the back of the line)will that be cash or charge?paper or plastic?


Ozonal Notes

Bush’s energy policy doesn’t work and history shows this.It seems like the folks making real progress in the energyfield are home power people—we’ve tripled in number inthe last decade. What do we know that they don’t?

PV Module AlertIf you are planning to buy PVs this summer, you may bedisappointed. Demand for PV is now exceeding the supply.People are buying PV modules faster than they are beingmanufactured. This increase in PV sales is being driven bythe recent utility blackouts.

In late May, I surveyed over 124 renewable energydealers nationwide. I asked them how long it would taketo get a PV module if they ordered it at that time. I alsoasked them if their businesses had grown within the lastsix months. Thirty-six dealers responded. They are waitingan average of two weeks for delivery of smaller PVmodules, and an average of two months on modules largerthan 85 watts. They also reported business increases from50 percent to over 300 percent.

This clearly shows that many more folks are consideringPV as an alternative to grid power. It also shows a need formore PV production to meet this increased demand. Weneed more PV dealers too, especially those who designand install complete systems.

Solar Energy FutureBush’s energy policy takes us back ten years into aninstant replay of his dad’s energy policy. This policy ofincreased coal burning, increased oil burning, andincreased use of nuclear power didn’t work ten yearsago, and it won’t be any more successful today. Thispolicy is what has gotten us into today’s energyshortages, high energy prices, blackouts, andenvironmental degradation.

While Dubya is stuck in the past, many Americans seem tohave other ideas. They are buying photovoltaics fasterthan ever before. They see the bright future of solarenergy, even if Bush cannot.

AccessRichard Perez, Home Power, PO Box 520, Ashland, OR97520 • 530-475-3179 • Fax: [email protected]

Jason Powell, c/o Home Power, PO Box 520, Ashland, OR97520 • 541-839-4662 • [email protected]


Back Issues of Home Power !Check out our Web site: www.homepower.comIt contains an index of all articles back to issue #1.

You can buy back issues individually:• $3.25 each for 13 and 17 through 20• $4.75 each for 21 through 45 (except for 35, 36, 38, 40, 41)

• $5.75 each for 46 through present (except for 57, 59–61, 63–67, 81, 82)

- OR -Deal #1: All available back issues for $100

Deal #2: 6 or more issues (of 21 through present) for $4.00 each (sent bound printed matter).

For U.S. ZIP codes only. See page 81 for international back issues.

Check with your local library—through interlibrary loan you can get back issues.The Jackson County Library in Oregon and the Alfred Mann Library at Cornell University have all issues.

Or, get the CD-ROMs—Solar2 (1–42), Solar3 (43–60), Solar4 (61–70), Solar5 (71–76), and Solar6 (77-82)

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Q&A

Homebrew Microhydro ProblemsHey gang! I’ve been trying to get a homegrown Peltonwheel to “pull its own” for the past three years or so byusing a Delco alternator with various creative wheelsattached to its shaft. It really zings along at about 55 psiwith a quarter inch nozzle. But as soon as I activate theelectromagnets in the alternator, it slows down so muchthat it just won’t put out enough to actually charge mybatteries. I get low volts and amps.

Of course I’m too cheap to buy real expensive parts, butis there a better permanent magnet motor to use, or asource for less expensive wheels you could suggest?Efficiency isn’t my strong suit, at any rate. I get 10 ampsin from solar, and in the winter I burn too much fuel.Anyway, I’m almost at the end of the creative, nospending stage, and thought I’d just ask. Thanks, Todd •[email protected]

Hiya Todd, First, you are probably using an internallyregulated Delco.You need to rip that regulator out orget an externally regulated machine. Then you feed thefield through a 25 Ω, 50 W rheostat (assuming you havea 12 V system). HP2 has a schematic of aengine/generator set up this way. It’s available on CD-ROM. Hydro works the same. Basically, you havelimited torque produced by the water pressure andvolume.You need to control the amount of current andvoltage going into the field so you can keep the RPM upand produce some power.

In a car, it’s pretty much a full-on field or full-off fieldscenario. If the alternator needs to grab a fewhorsepower from the motor to do that, you never evennotice.You haven’t got a few horsepower at your wheel.You could use a permanent magnet motor to eliminatethe field problem, but you have to use an in-line diodeto prevent draining the battery if the nozzle clogs or yourun out of water. Also, you’ll need to find a motor ratedto run at 24 V at least. Higher is better. The Lil Ottomotor, for example, is a 120 VDC motor. Unless youhave scored an actual Pelton somewhere, your wheel isprobably pretty inefficient as well. It all adds up, oneway or the other. Good Luck, Bob-O Schultze, ElectronConnection, Hornbrook, [email protected]

Computer Phantom LoadsI am a new subscriber and I’m at the research stage ofimplementing some renewable energy sources in myhome. I’m floored at the wealth of information in HomePower magazine—thank you.

My first step is evaluating our usage and taking thenecessary steps to get it down to a smart, comfortable,and affordable level for renewable sources (whatgluttons we’ve become). I loved the article on phantomloads, and I’m discovering that every KWH conservedhelps, but I have a question.

This may not actually be a phantom load because Iknow it’s happening. But I have always heard that ittakes more energy to turn a computer on and off if youuse it every day (and I do, since I work from home as aWeb designer/researcher) than if you just let it go intoscreen saver mode or sleep mode and turn off themonitor. Is that true? After reading the phantom loadarticle, I’m wondering just how many KWH that sleepmode is sucking away night after night. Any informationyou might have on this would be greatly appreciated.Thank you. Trish Boyles, North [email protected]

Hello Trish, This is something we know a lot aboutbecause we run an office with six assorted computers,all powered by PV and wind. Without any doubt, you willsave energy by completely powering down yourcomputer when it’s not in use. Exactly how muchdepends on your computer system, its monitor, and itsperipherals.

The biggest energy consumer is the monitor. The newer“Energy Star” compliant monitors use less energy when“asleep” than the older monitors do, but they are stillusing some energy. The rule of thumb we have here isthat if we are not going to use the computer for half anhour, we completely power down the monitor and putthe remainder of the computer to “sleep.” If we are notgoing to be using the computer for an hour, we powerdown the whole thing, including display and peripherals.

Pay attention to the peripherals. Their energyconsumption will add up if they are left operationalwhenever the computer is running. So power downunused peripherals, especially printers. I have many ofmy peripherals (modem, removable media drives,scanners, etc.) on a separate plug strip, and I keepthem powered down until I need them.

The idea that a computer system uses more energy tostart in the morning than it would consume if leftrunning all night is a myth. Richard Perez

Tires for Light TrucksI read Shari Prange’s article some time ago (HP71) onchoosing tires for EVs. Her observations about rollingresistance should be applied to gasoline-poweredvehicles as well as EVs. I have a light pickup truck andwould like to put D-rated street tires on it. What should Ilook for to decrease rolling resistance in such a tire?Michael

Q&A


Q&A

Hello Michael, The “D” rating on tires means they canhandle heavy loads. The good news, in terms of rollingresistance, is that the tire structure flexes less. The badnews is that the tires weigh more. Nobody is working onlow rolling resistance tires in this category. There are afew things you can do to help your gas mileage,however.

First, if you don’t need an aggressive tread for off-roador snowy conditions, stick to something with a “highwayrib” tread, which means fairly straight grooves, notknobs. Second, run your tires at their maximum ratedinflation. On D-rated truck tires, this is probably 65 psi.Shari Prange

Thermal ExchangeIf a PV panel collects enough solar thermal energyduring the typical summer day, what if a thermalexchanger could be incorporated to transfer this heat tothe dwelling’s hot water system? Many benefits couldcome from this: Your solar panels would run moreefficiently as a result of their lower operatingtemperature. Your resource consumption in supplyinghot water would be reduced, especially if this were inaddition to other practices like a pre-existing solarand/or waste drain thermal collector. You would alsoconserve space by reducing the footprint of individualsystems on the land or rooftop, to allow for eithergreater land cultivation or more room on the roof forexpansion or other needed systems. Thanks again foryour time, Chris Darul • [email protected]

Hello Chris. Over the years, several companies havetried to make a combination solar hot water collectorand solar-electric collector. All failed. Here are sometechnical reasons why.

PV and solar DHW operate in different temperatureranges. PVs like to be as cool as possible, attemperatures far below what we would want for “hot”water. Ideally we would like to never see a PV’stemperature go over 50°C, while this is just thebeginning of the temperature range we need for hotwater.

Expansion and contraction on any solar collector is areal problem. Electrical and plumbing connections workloose from expansion and contraction. To compoundthis problem, PV modules expand and contract atdifferent rates and amounts from a liquid-based thermalcollector. PV module encapsulation can be damaged byuneven expansion and contraction, reducing modulelife.

Combining PV and solar DHW into a single collectorsounds like a good idea, and it is. We just don’t havethe technology to pull it off yet. Richard Perez

Solar Tilt AngleWe own a small cabin far away from the grid inNorthern California, so we have decided to go solar-electric. Our estimated load is between 1 and 2 KWHper day. We are looking at six to eight 100 watt PVmodules.

We want to mount our modules flat on our high-pitched,55 degree roof. As I understand it, that pitch would besuitable for winter, but not for summer. My question is,what percent power loss can we expect from mountingat such an angle? Thank you, Harry Deemyad, Fairfield,California

Hello Harry, Folks who manually adjust the angle oftheir PV arrays usually do it four times a year. Forspring and fall, the array is set at the angle of the site’slatitude. In summer, the array is set at latitude minus 15degrees. In winter, the array is set at latitude plus 15degrees. Check out Richard Perez’s “PV ModuleAngles” article in HP36, page 14 for a detailed look atarray angles.

Depending on the exact latitude of your cabin innorthern California, 55 degrees is close to perfect foryour winter PV angle (latitude + 15 degrees). Whencompared to seasonal angle adjustments, having yourPVs fixed at this angle will result in approximately a 5percent decrease in output in the spring and fall. In thesummer, the decrease in output will be about 20percent.

Correctly sized PV systems typically show a significantenergy surplus in the summer. Since your array anglewill be fixed, and assuming you’re using the cabin year-round, having the PVs set at the winter angle ispreferable since winter months are when the least solarinsolation is available.

The reality is that people often leave their roof-mountedarrays set at the winter tilt angle. Adjusting roofmounted arrays can be inconvenient and dangerous,and adds wear and tear to the roofing material.Depending on your site, another option would be topole mount your PV array. This will allow you to easilymake seasonal adjustments. And because they are notmounted close to a hot roof surface, it will keep the PVsat a lower operating temperature, which increases theiroutput. Joe Schwartz

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Writing for Home Power

Writing forHome Powermagazine

H ome Power is a user’s technical journal. Wespecialize in hands-on, practical information aboutsmall-scale renewable energy systems. We try to

present technical material in an easy to understand andeasy to use format. Here are some guidelines for gettingyour renewable energy (RE) experiences printed in HomePower.

Informational ContentPlease include all the details! Be specific! We are moreinterested in specific information than in generalinformation. Write from your direct experience—HomePower is hands-on! Articles must be detailed enough thatour readers can actually use the information. Name names,and give us actual numbers, product names, and sources.

If you are writing about someone else’s system or project,we require a written release from the owner or otherprincipal before we can consider printing the article.

Article Style and LengthHome Power articles can be between 350 and 5,000 words.Length depends on what you have to say. Say it in as fewwords as possible.

We prefer simple declarative sentences that are short(fewer than twenty words) and to the point. We like thegenerous use of subheadings to organize the information.We highly recommend writing from within an outline. Checkout articles printed in Home Power. After you’ve studied afew, you will get a feeling for our style.

We edit all articles for accuracy, length, content,organization, and basic English. You can help by keepingyour sentences short, simple, and to the point. Our editingcrew will make your text shine.

PhotographsWe can work from any photographic print, slide, or negative.We prefer 4 by 6 inch color prints with no fingerprints orscratches. Do not write on the back of your photographs,since the ink can transfer to the front of the next photo.Please provide a caption and photo credit for each photo.Include some vertical format photos—you might even findyour system on HP’s cover. People are nice in photos; afuse box is only so interesting, even to solar nerds.

Digital photos should be at least 280 pixels per inch (ppi) atthe final printed size. This means that a column width photoshould be 1,000 pixels wide or more. A full page width photoshould be at least 2,300 pixels wide. Basically, set your

digital camera at its highest resolution, and cropthoughtfully. We prefer Photoshop files, but we can handlethe following formats in descending order of preference—EPS, TIFF, and JPEG.

Art, Schematics, & TablesSystem articles must contain a schematic drawing showingall wiring. Our art department can make gorgeousdiagrams, charts, and schematics from your roughsketches. If you want to submit a computer file of aschematic or other line art, please call or email us first.

For system articles, we require a load table listing all loads,with wattage and run time. We also require an itemized costtable listing each system component and its cost. We preferto have the tables come to us in Excel format. But we canuse them from any word processor or spreadsheet format ifthey are saved as “text only,” with tabs as the delimiterbetween cells.

Computer TalkWe can take text from most word processors. Save all wordprocessor files in “TEXT” or “ASCII TEXT” format. Thismeans removing all word processor formatting andgraphics. Use the “Save As Text” option in your wordprocessor.

If you want to send files larger than 5 MB (such as digitalphotos), use removable media and snail mail it to us. Wecan read ZIP disks (either Mac or IBM) and CD-ROMs. Youcan also FTP your large files to us at ftp.homepower.com, tothe “incoming” folder. Please let [email protected] after you have sent us files via FTP.

Putting it All TogetherWe get many more articles submitted than we can print.The most useful, specific, organized, and complete getpublished first. Here are the basic components of a greatHome Power article:

• Clearly written, well organized, and complete text, with astrong introductory paragraph, subheads for each majorsection, and a strong closing paragraph.

• Photos (plenty) with clear captions.• Cost table.• Load Table.• Other tables, charts, and diagrams as appropriate.• System schematic.• Complete Access information for author, installers,

consultants, suppliers, and manufacturers.

Have any questions? Give us a call Monday through Fridayfrom 9 to 5 Pacific and ask. Or send e-mail. This saveseveryone’s time. We hope to see your RE project in HomePower soon!

AccessHome Power magazine, PO Box 520, Ashland, OR 97520USA • 530-475-3179 • Fax: [email protected] • www.homepower.comFor FedEx, UPS or other shipping only (no postal service):312 N. Main St., Phoenix, OR 97535 • 541-512-0201


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FOR SALE: Sun Frost refrigerator, Solarjack well pump, Dankoffbooster pump, Trace Engineering C40 charge-Diversion & loadcontroller, Kyocera solar panels, Exide batteries. Call 520-339-4623.

24 VOLT INVERTERS FOR SALE. One Trace 2024 in as newcondition, $550.00. One Heart 2000 watt 24 volt with charger in asnew condition, $500.00. Off-Shore Marine 6883 four mile rd. Ada,MI 49301 ph616-676-0002

WANTED 32 volt dc to 120 volt ac INVERTER. 500 watt to 3000watt new or excellent condition. Also 32v appliances, tools from1910-1950 marine, railroad, farm electric era. E. BAYLY 1302W5th St, Duluth MN 55806 [email protected] 218-727-1550.

BUDGET SOLAR, your first choice for renewable energy products,is now online. Quality solar products, from educational kits andgadgets to PV modules and inverters, priced to fit every budget.Shop today at www.budgetsolar.com

JACOBS MODEL 18 1500 WATT Windmill & 56 ft. tower minusgovernor and blades. Generator is wired for 110 volts. Jacobstower is 3 legs free-standing. Generator serial no. E936. $1800O.B.O. 1-802-827-3298 eves

5TH WHEEL-HH II for sale-Featured in HP #66, P 40. 24’ RK,Manual Slide-out, AC/Heater/Frig/HW Heater etc. 214 Wts PVpanels, Freedom 10 charger/inverter, Link 1000 usage monitor, 4T-105 Trojans, 440 Amp Hrs. $9,500 OBO (520) 498-0811

TECHNICIAN in renewable energies, with support of electronicstechnician, would be interested in representing in Spainmanufacturing firms and/or electronic devices distributors for solarand/or wind energy systems. nieves garcia [email protected]

SOLAR POWERED HOME on 12.26 acres in Southern Oregon,1310 sq feet, internet ready, off the grid, $230,000 Call 541-535-3525 or see the house online at http://oregonsolar.homestead.com

GENERATOR FOR SALE: Pow’r Gard never used, 20KW top ofthe line unit with automatic transfer switch, fully enclosed, Ford 2.5liter, LP Gas, Quiet as a whistle! Valued $20K, make Offer...CallMark 828-389-1324

WHISPER 500 for sale only 2 years old (used for 6 months)asking $1,000. Also for sale, a 100’ guyed tower for $2,000.Please call with inquiries @ (715) 344-3632

BECOME A HOME Inspector. Approved home study. Freeliterature. P.C.D.I., Atlanta, Georgia. 800-362-7070 Dept.PPJP135.


MicroAds

EDTA RESTORES SULFATED Batteries. EDTA tetrasodium salt,info, catalog, $12/lb plus $3.50 ship & handle. Trailhead Supply325 E. 1165 N. Orem, UT 84057, (801) 225-3931 or (801) 226-6630 email: [email protected]://www.webspawner.com/users/trailheadsupply

HighTech Electric, California C-10 Electrical (General) ContractorLic.#766331, serving Northern California. Alternative / CustomHome Construction www.hightechelec.com (925) 634-0212

Murphy NC Mtn. home, quiet, peaceful, private, off grid,solar/hydro, 4 year old 3/3 cordwood masonry 2000+sf, masonrystove, tile floors downstairs, pine t&g upstairs, RF19 Sunfrostfridge/freezer, 6 burner commercial stove, rooftop garden, creekrunning across property, beautiful long distance views, 15.26+/-acres, 1000+sf workshop includes upstairs partially finishedapartment, gravity spring water, 2 hours from Atlanta,Chattanooga, or Asheville. Web site info available, asking 199K,828-837-4516 or [email protected].

SAVE MEDICINE LAKE VIDEO contains an urgent message topreserve a vital wildland and watershed in Northeastern CA fromgeothermal mining. Renewable energy and energy conservationwill star in this movie as the heroes. We are in midproduction andseeking funding. There is a 7 1/2 min. promotional video availablefor $20. Send check to David Munson PO Box 133, Mt. Shasta,CA 96067. Ph.# (530)239-8626. Check out our website. www.medicinelakevideo.org

COMPLETE OFF GRID SOLAR/WIND POWER SYSTEM BrandNew Whisper 3000HVLV high voltage wind turbine with Easywiremonitoring center 3kw wind turbine heavy duty blade option with84’ tower and guide line kit, 8 Siemens SR100 photovoltaic panelswith a 12 panel Wattsun dual axis tracker, Trace SW4024 inverterwith generator auto start , transformer, Diversion load heater, 12T105 trojan batteries, to store energy for days with no wind andsun light, 1000 ft UF-B 14-2+G, 250FT UF-B 8-2+G wire still onspools and all connecting wires Wind turbine and solar panels arestill in crate. Purchased December 1999 (y2k) The rest of thesystem is currently powering a 3000 SQ FT home for poweroutage backup It is a complete system from Windstream PowerSystem Inc. Vermont Tel - 802-658-0075 Paid 37,000 + new, willsacrifice for 25,000. Beats the cost of bringing electric to theremote locations. EMAIL [email protected] or call Mark@ 603-837-2195

CENTRAL VA - upgraded cottage and old mill on 27 Ac, 1+KWhydro potential. Beautiful location, remote, peaceful. $159,500(804) 248-9205 [email protected]

Energy efficient home construction. Less lumber, yet stronger, lessonsite labor and saves 50% on cooling and heating. Over 60,000homes have used this system www.InwestBuildingSystems.com

DEALER CLOSEOUT SALE Modules Water pumps Radios andmore. All items at cost. Send S.A.S.E. for list. Solar Box 587Roundup, MT 59072

GENERATORS FOR SALE: 10-New Generac 5KW with Briggs &Stratton engines, 5 gallon tanks, wheel kits Best Offer! Call Mark828-389-1324

A BREAKTHRU in windturbine technology. Penturbine available inkit form.modular, expandable, and self limiting. Send $3 for windsiting data and details to: f.m.hall, po box 95, chimacum, WA.98325

SEATTLE—AREA: Off-grid solar cedar home on 31 acres, privacyand mountain views. Visit at www.smashy.com/re/[email protected] or POB 314, Arlington, WA 98223

SATELLITE TV - Large selection of items at reasonable prices.We specialize in Big Dish TVRO C & Ku Band equipment. Checkus out at www.daveswebshop.com

CA certified whole foods cook, home chef, &/or elder transitionasst. Seeks Sonoma/Mendocino country coastal live-in situation. Ihave over 15 yrs. exp. in elder independent living with safety &dignity. Giving my client a safe feeling in their home; not be aloneALL the time. Gives family &/or friends peace of mind a personwith my experiences is close by. I can prepare whole foods tospecific diet. I also do edible landscaping critter care & can handlesm farm machinery. 707-592-5382

homesteadtechnology.com Engineering know-how in layman’slanguage. Power, phone, waste, security, you name it. Do-it-yourself and save thousands. Visit us online or at 503-439-9545.

TRACE DR3624 inverter w/standby charger. Works perfectly, usedfor 1.5 years. Dealer changeout. $950.00, you pay shipping (Ihave orig packaging). [email protected]

JACOBS 17.5 KW wind turbine with updated mastermind inverterand larger diameter shaft. No tower. 14’6” blades. $7000. 508-839-9547or geoff @apollopiano.com

ENGINE, ALTERNATOR Charger—More charge, less fuelportable or stationary Lit $1.00, charge carts Box 399 EphraimUtah 84627

FIVE-FOOT HIGH Nuclear Submarine Batteries are veryconservatively designed to outlast the lifetime of a submarine boat,(35 years). One of the great improvements is the use of calcium inthe very thick oxide-lead positive plate. This allows low gassingduring charging, which results in only adding water once every twoyears, and much lower charge loss, due to charge migrationduring stand-by. We estimate for home use you will get 50 yearsor better with good care. Each cell is 2.2 volts per cell X 7000amps per hour = 15,400 watts per hour, a 12 volt system = 6 cellsX 15,400 watts per hour = 92,400 watts per hour, this could run anaverage household for up to 45 days, (ganging more cells togethercan accommodate 24 volt, 48 volt, etc., systems). With a 48 voltsystem, (24 cells), 4 X 45 days = 180 days = 6 months. Whenpower is drawn from batteries at 200 amps per hour or less,instead of 7,000 amps per hour, as above, kilowatt-hour ratingsare increased 20 to 30% This is due to the lower heating effect ofthe acid. (1 kilowatt hour = 1000 watts per hour or a toaster or a1000 watt light bulb left on for one hour). Operating batteries atroom temperature increases the efficiency still more. Using theelectrolyte pumping system built into each cell increases theefficiency still more. This prevents acid from settling out, bypumping acid from the bottom of the cell to the top; this eliminatesthe problems of equalization. These batteries were made byExide, one of the leaders of battery manufacturing. Weight 1,068lbs. with acid; 900 lbs. dry; 14” X 14” X 58 in. high; fiberglass casefor extra strength; 22 gal. ordinary auto battery acid (available inmost cities for $1.50 per gal.); all new cells shipped dry on palletsFOB Brockton MA. Can be trickle charged from commercialpower, wind generators, or photovoltaic. You will find the quietpower of batteries is far better for peace of mind than a noisygenerator that has to be serviced & fueled regularly. Why deal withsmall batteries with short lifetimes, replace the weak link inphotovoltaic systems with true lifetime submarine battery cells!$3500 PER CELL. CALL: 508-586-8033


12 Volts and More — 102

AAA Solar Supply — 102

Abraham Solar Equipment — 111

ABS Alaskan — 130

Abundant Renewable Energy — 83

Adopt a Library — 137

Advanced Composting Systems — 118

Advanced Energy Inc — 63

Aeromax — 20

Alternative Energy Store — 87

Alternative Energy Systems Co — 130

American Solar Energy Society — 137

Aquadyne — 130

AstroPower — 5

B.Z. Products — 130

BackHome — 135

Backwoods Solar Electric Systems — 53

BargainSolar.com — 123

beaverpower.com — 130

Bergey Windpower — 4

Biodiesel — 112

Bogart Engineering — 107

BP Solar — 2 & 41

Brand Electronics — 111

C. Crane Company — 136

CheapestSolar.com — 97, 136, & 152

Communities magazine — 131

Controlled Energy Corporation — 113 &115

Creative Energy Technologies — 134

Dankoff Solar Products — 43

Direct Power and Water Corp — 61

E-Multisource — 63

Earth Solar — 107

Electro Automotive — 131 & 135

Electron Connection — 32

Electroportal — 118

Energía Total — 119

Energy Conservation Services — 54

Energy Designs — 78

Energy Outfitters — 134

Energy Systems & Design — 111

EPOWER — 129

Exeltech — 55

Eylander Electric — 118

Get a Job! — 149

Guerrilla Solar T-shirts — 94

Harris Hydroelectric — 90

Heaven’s Flame — 90

Heliodyne — 97

Heliotrope Thermal — 119

Hitney Solar Products — 112

Home Power Back Issues — 152

Home Power Biz Page — 81

Home Power CD-ROMs — 80

Home Power Sub Form — 80

Home Power T-shirts — 94

Homestead Solar — 119

Horizon Industries — 134

Hutton Communications — 79

Hydrocap — 123

Hydrogen Appliances — 152

Innovative Energy Systems Inc — 115

InterMountain Solar Technologies — 87

Inverter Repair — 118

IPP — 135

IRENEW — 62

Island Hot Tubs — 71

Jack Rabbit Energy Systems — 60

KTA Services Inc — 115

Kyocera Solar Inc — OBC

Matrix — 94

Meridan Energy Systems — 134

Moonlight Solar — 152

Morningstar — 73

MREA Workshops — 77

MrSolar.com — 136, 149, & 155

Natural Light Tubular Skylights — 70

NeatSolarStuff.com — 149

New Electric Vehicles — 155

New England Solar Electric Inc — 131

New Frontier — 134

New Mexico Solar Fiesta — 87

Newinli International Inc — 73

Northern Arizona Wind & Sun — 102

Northwest Energy Storage — 42

Norwood Industries — 115

Offline — 135

Outback Power Systems — 55

Planetary Systems — 73

Polar Power Inc — 113

PowerAssist.com — 17

PowerPod Corporation — 112

Preparation Enterprises — 90

Pulse Energy — 79

Quick Start Reading Special — 155

RAE Storage Battery Company — 129

Re-B energy — 136

Ready Reserve Foods — 106

Renewable Energy Videos — 90

RightHand Engineering — 137

Rolls Battery — 54

RV Power Products — 19

San Juan College — 152

Schott Applied Power Corporation — IBC

Siemens Solar Industries — 21

Simmons — 151

SMA America Inc — 53

smartwindow.com — 137

Solar Depot — IFC

Solar Electric Inc — 90

Solar Energy International — 91

Solar Pathfinder — 127

Solar Plexus — 83

Solar Solutions Ltd — 149

Solar Village — 79

Solar Wind Works — 87

Solar6 CD-ROM — 95

Solardyne Corporation — 119

SolarHost.com — 89

SolarRoofs.com — 106

SolarSense.com — 9

SolarServices.com — 71

Solartech 3000 — 30

SolEnergy — 71

SolFest2001 — 78

SOLutions — 103

Southwest PV Systems & Supply — 83

Southwest Solar — 127

Southwest Windpower — 31

Stavy, Michael — 155

Sun Electronics — 112

Sun Frost — 78

SunAmp Power Company — 71

Sunweaver — 60

SunWize — 79

Texas RE Roundup — 72

Thermodynamics — 154

Tractel Inc — 83

Trojan — 43

U.S. Battery — 18

UniRac — 113

US Carburetion Inc — 136

Vanner Power Systems — 42

Wattsun Trackers — 131

Xantrex — 1, 33, & 61

Zephyr Industries Inc — 130

Zomeworks — 73

Index to Advertisers

Colorado Earthship:Solar and wind power for a natural home

The Basics of Solar Hot Water: Find the system that’s right for you

Sustainable Solar Logging: A sawmill gets quiet in the Rockies

Do-It-Yourself LED Flashlight: Convert a Mag-Lite for extended play

Remote Internet...Finally: Off-gridders go on-line with StarBand

ISSUE #84 August / September 2001$4.75 U.S.

$7.00 CAN.Display until October 1

Blackout Buster: The backup power system to get you through

NOW: I use renewableenergy for (check onesthat best describe yoursituation)

All electricity

Most electricity

Some electricity

Backup electricity

Recreational electricity(RVs, boats, camping)

Vacation or secondhome electricity

Transportation power(electric vehicles)

Water heating

Space heating

Business electricity

In The FUTURE: I plan touse renewable energy for(check ones that bestdescribe your situation)

All electricity

Most electricity

Some electricity

Backup electricity

Recreational electricity(RVs, boats, camping)

Vacation or secondhome electricity

Transportation power(electric vehicles)

Water heating

Space heating

Business electricity

RESOURCES: My site(s)have the followingrenewable energyresources (check all that apply)

Solar power

Wind power

Hydro power

Biomass

Geothermal power

Tidal power

Other renewableenergy resource(explain)

The GRID: (check all thatapply)

I have the utility grid atmy location.

I pay ______¢ for gridelectricity (cents perkilowatt-hour).

____% of my totalelectricity is purchasedfrom the grid.

I sell my excesselectricity to the grid.

The grid pays me _____¢for electricity (centsper kilowatt-hour).

(continued on reverse)

Home Power Subscription$22.50 per year (6 issues) to U.S. Zip Codes via 2nd Class U.S. Mail$36.00 per year (6 issues) to U.S. Zip Codes via 1st Class U.S. Mail$30.00 (U.S. drawn on U.S. Bank) International Surface Mail, see pg. 81 for Air RatesHome Power magazine, PO Box 520, Ashland, OR 97520Subscribe online at: www.homepower.comSubscriptions: 800-707-6585 (inside USA) or 541-512-0201 or Fax 541-512-0343Editorial: 530-475-3179 or Fax 530-475-0836

To subscribe to Home Power, please fill out the sub form below, enclose payment as a check, money order, orVisa/MasterCard, and mail this form. Tape the form well or use an envelope so your check doesn't fall out. Your sub orrenewal will start with HP's next regularly scheduled issue. Please allow up to ten weeks for the start of your 2nd class sub.For those wishing International Subscriptions or Back Issues of Home Power, please see page 81.

New 2nd Class Sub-$22.50to USA Zip Codes

New 1st Class Sub-$36to USA Zip Codes

Sub RenewalSpecify 1st or 2nd Class

Change of Address(include old address)

Gift SubscriptionFrom (give your name and address here)

DO YOU WANT US TO SEND YOU A SUBSCRIPTION RENEWAL NOTICE?The number of the last issue in your subscription is printed on your mailing label.

Yes, remind me by mail when my subscription runs out. No, I’ll check my mailing label so we can save energy & paper.

PLEASE CLEARLY PRINT THE COMPLETE NAME AND ADDRESS FOR THIS SUBSCRIPTION:

NAME

STREET

CITY STATE ZIP

PHONE EMAIL

The following information about your renewable energy usage helps us produce a magazine to better serve your interests.This information will be held confidential. We do not sell our mailing list. Completion of the rest of this form is not necessary toreceive a subscription, but we would greatly appreciate your input.

Credit Card Orders: please check the type of card you have and fill in the information below.

Signature (as shown on card) _________________________________ Exp. Date ___________

Credit Card Number ________________________________________ Amount $ ____________

HP#84

FOLD HERE AND TAPE EDGES

FOLD HERE AND TAPE EDGES

NOW FUTURE

Photovoltaic modules

Wind generator

Hydroelectric generator

Battery charger

Instrumentation

Batteries

Inverter

Controls

PV tracker

Engine/generator

I now use, or plan to use in the future, the following renewable energy equipment (check all that apply):

NOW FUTURE

Methane digester

Thermoelectric generator

Solar oven or cooker

Solar water heater

Wood-fired water heater

Solar space heating system

Hydrogen cells (electrolyzers)

Fuel cells

RE-powered water pump

Electric vehicle

Please write to us here. Tell us what you like and don't like about Home Power. Tell us what you would like to read about infuture issues. Thanks for your attention and support.

Check here if it is OK to print your comments as a letter to Home Power.

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HP#84

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